ORIGINAL CONTRIBUTION
Equivocal Effect of Intraoperative Fluorescence Angiography on Colorectal Anastomotic Leaks Cindy Kin, M.D. • Hong Vo, M.D. • Lindsay Welton, B.A. Mark Welton, M.D., M.H.C.M. Department of Surgery, Stanford University Medical Center, Stanford, California
BACKGROUND: Intraoperative fluorescence angiography is beneficial in several surgical settings to assess tissue perfusion. It is also used to assess bowel perfusion, but its role in improving outcomes in colorectal surgery has not been studied. OBJECTIVE: The purpose of this work was to determine whether intraoperative angiography decreases colorectal anastomotic leaks. DESIGN: This was a case-matched retrospective study in which patients were matched 1:1 with respect to sex, age, level of anastomosis, presence of a diverting loop ileostomy, and preoperative pelvic radiation therapy. SETTINGS: The study was conducted at an academic
medical center. PATIENTS: Patients who underwent colectomy or proctectomy with primary anastomoses were included. INTERVENTIONS: The intraoperative use of fluorescence angiography to assess perfusion of the colon for anastomosis was studied. MAIN OUTCOME MEASURES: Anastomotic leak within 60 days and whether angiography changed surgical management were the main outcomes measured. RESULTS: Case matching produced 173 pairs. The groups were also comparable with respect to BMI, smoking status, diabetes mellitus, surgical indications, Financial Disclosure: Dr Welton was a paid consultant and speaker for Novadaq/Lifecell, the manufacturer of the SPY intraoperative fluorescence angiography system. Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Hollywood, FL, May 17 to 21, 2014. Correspondence: Cindy Kin, M.D., Stanford University Medical Center, Department of Surgery, 300 Pasteur Dr, H3680K, Stanford, CA 94305. E-mail: [email protected] Dis Colon Rectum 2015; 58: 582–587 DOI: 10.1097/DCR.0000000000000320 © The ASCRS 2015
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and type of resection. In patients who had intraoperative angiography, 7.5% developed anastomotic leak, whereas 6.4% of those without angiography did (p value not significant). Univariate analysis revealed that preoperative pelvic radiation, more distal anastomosis, surgeon, and diverting loop ileostomy were positively associated with anastomotic leak. Multivariate analysis demonstrated that level of anastomosis and surgeon were associated with leaks. Poor perfusion of the proximal colon seen on angiography led to additional colon resection before anastomosis in 5% of patients who underwent intraoperative angiography. LIMITATIONS: The retrospective study design with the use of historical control subjects, selection bias, and small sample size were limitations to this study. CONCLUSIONS: Intraoperative fluorescence angiography to assess the perfusion of the colon conduit for anastomosis was not associated with colorectal anastomotic leak. Perfusion is but one of multiple factors contributing to anastomotic leaks. Additional studies are necessary to determine whether this technology is beneficial for colorectal surgery. KEY WORDS: Anastomotic leak; Colorectal anastomoses; Fluorescence angiography.
A
nastomotic leaks after colorectal resections result in significant morbidity, including the need for additional procedures or operations, fecal diversion, prolonged hospital stays, poor functional outcomes, and, in the most devastating circumstances, death.1,2 Leaks occurring after resections for colorectal cancer may adversely affect cancer-related, disease-free, and overall survival.2 Despite technological advancements and standard surgical techniques, anastomotic leaks still occur in 2% to 13% of colorectal resections.3–9 Adequate tissue perfusion promotes anastomotic healing.10–12 Traditional intraoperative techniques used to assess bowel perfusion include gross examination of the Diseases of the Colon & Rectum Volume 58: 6 (2015)
Copyright © The American Society of Colon & Rectal Surgeons, Inc. Unauthorized reproduction of this article is prohibited.
583
Diseases of the Colon & Rectum Volume 58: 6 (2015)
bowel wall and its blood supply, Doppler ultrasound, and fluorescein dye angiography (Wood’s lamp). Intraoperative laser fluorescence angiography with indocyanine green dye is a recent technology that allows surgeons to assess tissue perfusion. It has been shown to be a helpful adjunct in arterial revascularization operations and solid organ transplantations to assess graft and vessel p atency.13,14 In reconstructive breast surgery, intraoperative laser fluorescence angiography better predicts skin flap necrosis after mastectomy than clinical judgment and fluorescein dye angiography.15 Although its beneficial role is demonstrated in these other surgical specialties, it remains unclear whether intraoperative laser fluorescence angiography offers a similar benefit in colorectal resections with regard to preventing anastomotic leak. Our aim was to perform a preliminary study to determine whether the use of intraoperative laser fluorescence angiography affected the anastomotic leak rate in colon and rectal resections.
MATERIALS AND METHODS We performed a retrospective review of all of the patients who underwent colon and rectal surgery with primary anastomosis from November 2005 through December 2012 by colorectal surgeons at our academic medical institution with the approval of the institutional review board. Patients ≥18 years of age who underwent elective colon or rectal resections with a primary anastomosis were included. Intraoperative fluorescence angiography was introduced to the institution in 2009 and was used thereafter in a proportion of patients for assessment of the proximal colonic conduit in colocolonic, colorectal, and coloanal anastomoses. Perineal proctectomies, ileocolic and ileorectal anastomoses, and total proctocolectomy with IPAAs were excluded, because fluorescence angiography was never used in these patients. Patients were case matched in a 1:1 ratio using the criteria of sex, age (±5 years), level of anastomosis (±1 cm), history of neoadjuvant pelvic radiation therapy, and use of a diverting loop ileostomy. If there were multiple eligible matches to 1 patient, then a computer program was used to randomly pick one. The nonangiography cases were drawn from the period of time before the introduction of the technology to our institution to partially mitigate the effect of selection bias. The primary outcome was anastomotic leak o ccurring within 60 days of the initial operation. An anastomotic leak was defined by at least one of the following criteria: 1) an anastomotic defect noted on physical examination, 2) an anastomotic defect confirmed in the operating room, 3) an anastomotic defect seen on proctoscopy, 4) radiologic evidence of a leak consisting of either a defect in the anastomosis and an adjacent fluid collection, or stranding or the extravasation of rectal contrast into the
extraluminal space, or 5) clinical evidence of a leak such as feculent output from a pelvic drain. The secondary outcome was whether the results of intraoperative fluorescence angiography changed surgical management. All of the patients received preoperative antibiotics. Mechanical bowel preparation was at the discretion of the attending surgeon. In all of the patients, the attending surgeons determined the suitability of the colon to be used for anastomosis by gross examination. For the angiography group, 3 mL of indocyanine green dye followed by a 10-mL saline flush was injected into a peripheral vein, and real-time fluorescence images using the SPY Imaging System (Novadaq Technologies Inc, Bonita Springs, FL) were observed. Portions of the bowel with greater fluorescence relative to other areas indicated better perfusion. Bowel with poor perfusion was resected back to well-perfused bowel, even if it had seemed viable on gross examination. Reassessment of proximal bowel perfusion was not conducted after excision. Perfusion of the distal rectal stump was not evaluated, because the angiography system often could not visualize structures in the pelvis, especially in laparoscopic cases. The 6 surgeons that contributed cases to this series underwent training on how to use the system and agreed regarding how to interpret the angiography images. For the surgeon-level analysis, the surgeons were ranked based on their leak rates. Table 1. Demographics, diagnoses, and comorbidities of patients who underwent colorectal resections with anastomoses, with and without intraoperative fluorescence angiography, from 2009 to 2012 Variable Age, y, mean ± SD Sex, % Women Men BMI, kg/m2, mean ± SD Smoking status, % Never smoker Former smoker Current smoker Diabetes mellitus, % Anemia, %a Hemoglobin, g/dL, mean ± SD ASA status, % 1 2 3 4 Charlson comorbidity index, mean ± SD Surgical indications, % Diverticular disease Cancer IBD Preoperative pelvic radiation therapy, %
Angiography (N = 173)
No angiography (N = 173)
58.2 ± 13.2
58.1 ± 13.2
46 54 27.0 ± 4.9
46 54 26.5 ± 5.3
65 25 10 13 26 13.2 ± 1.5
60 29 11 10 30 13.1 ± 1.8
2 43 53 2 4.5 ± 2.4
3 47 50 0 4.5 ± 2.5
27.0 57.0 2.3 20
18.0 61.0 3.5 20
p 0.90 –
0.33 0.60
0.50 0.53 0.91 0.19
0.78 0.18
1
Based on World Health Organization criteria for anemia; not adjusted for smoking status.
a
Copyright © The American Society of Colon & Rectal Surgeons, Inc. Unauthorized reproduction of this article is prohibited.
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Kin et al: Intraoperative Angiography and Leak Rate
Table 2. Operative and postoperative factors in patients undergoing colon or rectal resections with anastomosis, with and without intraoperative angiography, 2009–2012 Variable Type of operation (anastomosis), %a Left colectomy (colon to colon) Sigmoid colectomy (colon to top of rectum) Proctosigmoidectomy (colon to proximal rectum) Low proctosigmoidectomy (colon to distal rectum) Ultralow proctosigmoidectomy (colon to anus) Laparoscopic, % Mean distance from anal verge in colorectal and coloanal anastomoses, mean ± SD, in cma,b Diverting loop ileostomy, % Surgeon use of angiography, range, % Anastomotic leak within 60 d, % Time after index operation, d Diagnostic modality, % Clinical diagnosis Radiological confirmation Initial intervention, % Nonoperativec Reoperation
Angiography (N = 173)
No angiography (N = 173)
6 40 34 17 3 64 11.1 ± 4.2
3 43 34 17 3 42 11.3 ± 4.3
17 41–63 7.5 (n = 13) 17 ± 12
17 37–59 6.4 (n = 11) 19 ± 18
15 85
9 91
46 54
64 36
p 0.77
Equivocal Effect of Intraoperative Fluorescence Angiography on Colorectal Anastomotic Leaks Cindy Kin, M.D. • Hong Vo, M.D. • Lindsay Welton, B.A. Mark Welton, M.D., M.H.C.M. Department of Surgery, Stanford University Medical Center, Stanford, California
BACKGROUND: Intraoperative fluorescence angiography is beneficial in several surgical settings to assess tissue perfusion. It is also used to assess bowel perfusion, but its role in improving outcomes in colorectal surgery has not been studied. OBJECTIVE: The purpose of this work was to determine whether intraoperative angiography decreases colorectal anastomotic leaks. DESIGN: This was a case-matched retrospective study in which patients were matched 1:1 with respect to sex, age, level of anastomosis, presence of a diverting loop ileostomy, and preoperative pelvic radiation therapy. SETTINGS: The study was conducted at an academic
medical center. PATIENTS: Patients who underwent colectomy or proctectomy with primary anastomoses were included. INTERVENTIONS: The intraoperative use of fluorescence angiography to assess perfusion of the colon for anastomosis was studied. MAIN OUTCOME MEASURES: Anastomotic leak within 60 days and whether angiography changed surgical management were the main outcomes measured. RESULTS: Case matching produced 173 pairs. The groups were also comparable with respect to BMI, smoking status, diabetes mellitus, surgical indications, Financial Disclosure: Dr Welton was a paid consultant and speaker for Novadaq/Lifecell, the manufacturer of the SPY intraoperative fluorescence angiography system. Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Hollywood, FL, May 17 to 21, 2014. Correspondence: Cindy Kin, M.D., Stanford University Medical Center, Department of Surgery, 300 Pasteur Dr, H3680K, Stanford, CA 94305. E-mail: [email protected] Dis Colon Rectum 2015; 58: 582–587 DOI: 10.1097/DCR.0000000000000320 © The ASCRS 2015
582
and type of resection. In patients who had intraoperative angiography, 7.5% developed anastomotic leak, whereas 6.4% of those without angiography did (p value not significant). Univariate analysis revealed that preoperative pelvic radiation, more distal anastomosis, surgeon, and diverting loop ileostomy were positively associated with anastomotic leak. Multivariate analysis demonstrated that level of anastomosis and surgeon were associated with leaks. Poor perfusion of the proximal colon seen on angiography led to additional colon resection before anastomosis in 5% of patients who underwent intraoperative angiography. LIMITATIONS: The retrospective study design with the use of historical control subjects, selection bias, and small sample size were limitations to this study. CONCLUSIONS: Intraoperative fluorescence angiography to assess the perfusion of the colon conduit for anastomosis was not associated with colorectal anastomotic leak. Perfusion is but one of multiple factors contributing to anastomotic leaks. Additional studies are necessary to determine whether this technology is beneficial for colorectal surgery. KEY WORDS: Anastomotic leak; Colorectal anastomoses; Fluorescence angiography.
A
nastomotic leaks after colorectal resections result in significant morbidity, including the need for additional procedures or operations, fecal diversion, prolonged hospital stays, poor functional outcomes, and, in the most devastating circumstances, death.1,2 Leaks occurring after resections for colorectal cancer may adversely affect cancer-related, disease-free, and overall survival.2 Despite technological advancements and standard surgical techniques, anastomotic leaks still occur in 2% to 13% of colorectal resections.3–9 Adequate tissue perfusion promotes anastomotic healing.10–12 Traditional intraoperative techniques used to assess bowel perfusion include gross examination of the Diseases of the Colon & Rectum Volume 58: 6 (2015)
Copyright © The American Society of Colon & Rectal Surgeons, Inc. Unauthorized reproduction of this article is prohibited.
583
Diseases of the Colon & Rectum Volume 58: 6 (2015)
bowel wall and its blood supply, Doppler ultrasound, and fluorescein dye angiography (Wood’s lamp). Intraoperative laser fluorescence angiography with indocyanine green dye is a recent technology that allows surgeons to assess tissue perfusion. It has been shown to be a helpful adjunct in arterial revascularization operations and solid organ transplantations to assess graft and vessel p atency.13,14 In reconstructive breast surgery, intraoperative laser fluorescence angiography better predicts skin flap necrosis after mastectomy than clinical judgment and fluorescein dye angiography.15 Although its beneficial role is demonstrated in these other surgical specialties, it remains unclear whether intraoperative laser fluorescence angiography offers a similar benefit in colorectal resections with regard to preventing anastomotic leak. Our aim was to perform a preliminary study to determine whether the use of intraoperative laser fluorescence angiography affected the anastomotic leak rate in colon and rectal resections.
MATERIALS AND METHODS We performed a retrospective review of all of the patients who underwent colon and rectal surgery with primary anastomosis from November 2005 through December 2012 by colorectal surgeons at our academic medical institution with the approval of the institutional review board. Patients ≥18 years of age who underwent elective colon or rectal resections with a primary anastomosis were included. Intraoperative fluorescence angiography was introduced to the institution in 2009 and was used thereafter in a proportion of patients for assessment of the proximal colonic conduit in colocolonic, colorectal, and coloanal anastomoses. Perineal proctectomies, ileocolic and ileorectal anastomoses, and total proctocolectomy with IPAAs were excluded, because fluorescence angiography was never used in these patients. Patients were case matched in a 1:1 ratio using the criteria of sex, age (±5 years), level of anastomosis (±1 cm), history of neoadjuvant pelvic radiation therapy, and use of a diverting loop ileostomy. If there were multiple eligible matches to 1 patient, then a computer program was used to randomly pick one. The nonangiography cases were drawn from the period of time before the introduction of the technology to our institution to partially mitigate the effect of selection bias. The primary outcome was anastomotic leak o ccurring within 60 days of the initial operation. An anastomotic leak was defined by at least one of the following criteria: 1) an anastomotic defect noted on physical examination, 2) an anastomotic defect confirmed in the operating room, 3) an anastomotic defect seen on proctoscopy, 4) radiologic evidence of a leak consisting of either a defect in the anastomosis and an adjacent fluid collection, or stranding or the extravasation of rectal contrast into the
extraluminal space, or 5) clinical evidence of a leak such as feculent output from a pelvic drain. The secondary outcome was whether the results of intraoperative fluorescence angiography changed surgical management. All of the patients received preoperative antibiotics. Mechanical bowel preparation was at the discretion of the attending surgeon. In all of the patients, the attending surgeons determined the suitability of the colon to be used for anastomosis by gross examination. For the angiography group, 3 mL of indocyanine green dye followed by a 10-mL saline flush was injected into a peripheral vein, and real-time fluorescence images using the SPY Imaging System (Novadaq Technologies Inc, Bonita Springs, FL) were observed. Portions of the bowel with greater fluorescence relative to other areas indicated better perfusion. Bowel with poor perfusion was resected back to well-perfused bowel, even if it had seemed viable on gross examination. Reassessment of proximal bowel perfusion was not conducted after excision. Perfusion of the distal rectal stump was not evaluated, because the angiography system often could not visualize structures in the pelvis, especially in laparoscopic cases. The 6 surgeons that contributed cases to this series underwent training on how to use the system and agreed regarding how to interpret the angiography images. For the surgeon-level analysis, the surgeons were ranked based on their leak rates. Table 1. Demographics, diagnoses, and comorbidities of patients who underwent colorectal resections with anastomoses, with and without intraoperative fluorescence angiography, from 2009 to 2012 Variable Age, y, mean ± SD Sex, % Women Men BMI, kg/m2, mean ± SD Smoking status, % Never smoker Former smoker Current smoker Diabetes mellitus, % Anemia, %a Hemoglobin, g/dL, mean ± SD ASA status, % 1 2 3 4 Charlson comorbidity index, mean ± SD Surgical indications, % Diverticular disease Cancer IBD Preoperative pelvic radiation therapy, %
Angiography (N = 173)
No angiography (N = 173)
58.2 ± 13.2
58.1 ± 13.2
46 54 27.0 ± 4.9
46 54 26.5 ± 5.3
65 25 10 13 26 13.2 ± 1.5
60 29 11 10 30 13.1 ± 1.8
2 43 53 2 4.5 ± 2.4
3 47 50 0 4.5 ± 2.5
27.0 57.0 2.3 20
18.0 61.0 3.5 20
p 0.90 –
0.33 0.60
0.50 0.53 0.91 0.19
0.78 0.18
1
Based on World Health Organization criteria for anemia; not adjusted for smoking status.
a
Copyright © The American Society of Colon & Rectal Surgeons, Inc. Unauthorized reproduction of this article is prohibited.
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Kin et al: Intraoperative Angiography and Leak Rate
Table 2. Operative and postoperative factors in patients undergoing colon or rectal resections with anastomosis, with and without intraoperative angiography, 2009–2012 Variable Type of operation (anastomosis), %a Left colectomy (colon to colon) Sigmoid colectomy (colon to top of rectum) Proctosigmoidectomy (colon to proximal rectum) Low proctosigmoidectomy (colon to distal rectum) Ultralow proctosigmoidectomy (colon to anus) Laparoscopic, % Mean distance from anal verge in colorectal and coloanal anastomoses, mean ± SD, in cma,b Diverting loop ileostomy, % Surgeon use of angiography, range, % Anastomotic leak within 60 d, % Time after index operation, d Diagnostic modality, % Clinical diagnosis Radiological confirmation Initial intervention, % Nonoperativec Reoperation
Angiography (N = 173)
No angiography (N = 173)
6 40 34 17 3 64 11.1 ± 4.2
3 43 34 17 3 42 11.3 ± 4.3
17 41–63 7.5 (n = 13) 17 ± 12
17 37–59 6.4 (n = 11) 19 ± 18
15 85
9 91
46 54
64 36
p 0.77
![[Risk factors for colorectal anastomotic leaks].](/assets/img/hold.png)
