European Journal of Cardio-Thoracic Surgery Advance Access published February 26, 2015

ORIGINAL ARTICLE

European Journal of Cardio-Thoracic Surgery (2015) 1–6 doi:10.1093/ejcts/ezv021

External validation of the Ferguson pulmonary risk score for predicting major pulmonary complications after oesophagectomy† J. Matthew Reinersmana, Mark S. Allena, Claude Deschampsa, Mark K. Fergusonb, Francis C. Nicholsa, K. Robert Shena, Dennis A. Wiglea and Stephen D. Cassivia,* a b

Division of General Thoracic Surgery, Department of Surgery, Mayo Clinic, Rochester, MN, USA Department of Surgery, The University of Chicago, Chicago, IL, USA

* Corresponding author. Division of General Thoracic Surgery, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905, USA. Tel: +1-507-2660911; fax: +1-507-2840058; e-mail: [email protected] (S.D. Cassivi). Received 13 September 2014; received in revised form 23 December 2014; accepted 2 January 2015

Abstract OBJECTIVES: Pulmonary complications remain a frequent cause of morbidity in patients undergoing oesophagectomy. Risk screening tools assist in patient stratification. Ferguson proposed a risk score system to predict major pulmonary complications after oesophagectomy. Our objective was to externally validate this risk score system. METHODS: We analysed our institutional database for patients undergoing oesophagectomy for cancer from August 2009 to December 2012. We analysed patients who had complete documentation of variables used in the Ferguson risk score calculation: forced expiratory volume in the 1 s, diffusion capacity of the lung for carbon monoxide, performance status and age. One hundred and thirty-six patients qualified for analysis in the validation study. Outcome variables measured included major pulmonary complications, defined as need for reintubation for respiratory failure and pneumonia. The risk score was then calculated for each individual based on the model. Incidence of major pulmonary events was assessed in the five risk class groupings to assess the discriminative ability of the Ferguson score. RESULTS: Major pulmonary complications occurred in 35% of patients (47/136). Overall mortality was 6% (8/136). Patients were grouped into five risk categories according to their Ferguson pulmonary risk score: 0–2, 8 patients (6%); 3–4, 24 patients (18%); 5–6, 49 patients (36%); 29 patients (21%); 9–14, 26 patients (19%). The incidence of major pulmonary complications in these categories was 0, 17, 20, 41 and 77%, respectively. The accuracy of the risk score system for predicting major pulmonary complications was 76% (P < 0.0001). CONCLUSIONS: This pulmonary risk scoring system is a reliable instrument to be used during the preoperative phase to differentiate patients who may be at higher risk for pulmonary complications after oesophagectomy. These data can assist in patient selection, and in patient education/informed consent and can guide postoperative management. Keywords: Oesophageal neoplasms • Oesophagectomy • Patient selection • Outcomes • Pneumonia • Respiratory insufficiency

INTRODUCTION Oesophageal cancer is the sixth leading cause of cancer-related mortality worldwide, and has the fastest growing incidence of any cancer in the USA [1]. Surgical resection is the mainstay of therapy, offering a chance of long-term survival. Oesophagectomy is associated with risk, in both short-term complications and longer term loss of quality of life. Over half of the patients suffer at least one adverse postoperative event [2]. Surgeons have a need for methods to better predict risk for these patients. Risk stratification is a valuable tool to preoperatively identify which patients are at increased risk. An addition to risk stratification is the advent of risk scoring systems. These allow each patient to be stratified into a † Presented at the 28th Annual Meeting of the European Association for CardioThoracic Surgery, Milan, Italy, 11–15 October 2014.

predictive group based on the system. This technique provides an estimate of an individual’s actual risk. Pulmonary complications remain a frequent postoperative event after oesophagectomy, significantly contributing to prolonged length of stay and postoperative mortality. Ferguson et al. [3] developed a risk scoring system to predict postoperative pulmonary complication following oesophagectomy. These data were collected from their institutional database over 30 years. Utilizing these data, they created a score system using four factors: age, performance status, forced expiratory volume in the first second expressed as percent predicted (FEV1%) and diffusion capacity of the lung for carbon monoxide expressed as percent predicted (DLCO%). Using weighted scores of these four variables, the scoring system predicted pulmonary complications with an accuracy of 70.8%. Our aim was to externally validate the risk score’s accuracy using our institutional data.

© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

THORACIC

Cite this article as: Reinersman JM, Allen MS, Deschamps C, Ferguson MK, Nichols FC, Shen KR et al. External validation of the Ferguson pulmonary risk score for predicting major pulmonary complications after oesophagectomy. Eur J Cardiothorac Surg 2015; doi:10.1093/ejcts/ezv021.

J.M. Reinersman et al. / European Journal of Cardio-Thoracic Surgery

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MATERIALS AND METHODS The study was reviewed, and approved by our Institutional Review Board. Specific patient consent for this study was waived. We performed a retrospective analysis of our prospectively collected patient database for patients undergoing oesophagectomy for cancer from August 2009 to December 2012. We collected variables necessary to calculate the Ferguson pulmonary risk score: age, performance status, FEV1 and DLCO%. Pulmonary function tests utilized for this study were obtained prior to resection but after neoadjuvant therapy, if administered. We identified 136 patients that qualified for analysis in the validation study. Two-hundred and seven patients were excluded during the inclusion period secondary to insufficient variables to calculate the risk score. We then analysed the presence of outcome variables. Major outcome variables were major pulmonary complications, defined as need for reintubation for isolated respiratory insufficiency and/or pneumonia, documented by fever, elevated white blood cell count and pulmonary infiltrate requiring antibiotic therapy. Other outcomes evaluated were mortality, defined as 30-day operative or in-hospital mortality. Oesophagectomy was partial or total, and performed utilizing the following approaches: Ivor Lewis, transhiatal, McKeown modification of the Ivor Lewis approach, total or hybrid minimally invasive approaches or resection without reconstruction. Patients were managed according to our standard institution protocol with epidural catheters for pain management, early extubation and ambulation and early enteral nutrition via jejunostomy tube (Supplemental material). The statistical analysis was conducted using SAS version 9.3 (SAS Institute, Inc., Cary, NC, USA). For univariate comparisons, chi-square tests were utilized to evaluate the association between categorical variables and occurrence of pulmonary complication; when expected counts were low, Fisher’s exact test was used. The association between continuous variables and pulmonary complications was analysed using t-tests and Wilcoxon rank-sum tests. The Ferguson pulmonary risk score is a 5-level risk score comprising four weighted factors (age, performance status, FEV1% and DLCO%), each having 5 different score categories from 0 to 4 (Table 1) [3]. According to the individual weighted scores assigned to each factor, an aggregate score was calculated for each patient. Patients were then grouped into the five different categories of risk according to their scores, and incidence of major pulmonary events was assessed in each class.

Table 1: Ferguson weighted pulmonary complications

scoring

system

for

Assigned score value

0

1

2

3

4

Age Performance Status (Zubrod/ECOG) FEV1% DLCO%

80 4

≥100 ≥100

90–99.9 90–99.9

80–89.9 80–89.9

70–79.9 70–79.9

External validation of the Ferguson pulmonary risk score for predicting major pulmonary complications after oesophagectomy†.

Pulmonary complications remain a frequent cause of morbidity in patients undergoing oesophagectomy. Risk screening tools assist in patient stratificat...
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