Preoperative assessment of patient comorbidities before left colectomy: Comparison between ASA performance status scale and a new computed tomography physical status score

Purpose: To compare a newly developed preoperative computed tomography physical status (CT-PS) score with the American Society of Anesthesiology performance status (ASA-PS) scale in the assessment of patient preoperative health status and stratification of perioperative risk before left colectomy.

Materials and methods: Preoperative chest-abdomen-pelvis CT examinations of patients who were scheduled to undergo elective laparoscopic left colonic resection for cancer in two centers were reviewed by two radiologists blinded to clinical data for the presence of several key imaging features in order to assess general, cardiac, pulmonary, abdominal, renal, vascular and musculoskeletal status. CT examinations of patients from center 1 were used to build a CT-PS score to predict ASA-PS≥III. CT-PS score was further validated using an external cohort of patients from center 2.

Results: During a 2-year period, 117 consecutive patients (63 men, 54 women; mean age, 65±13 [SD] years; age range: 53-90 years) who underwent laparoscopic left colectomy for cancer in center 1 (66 patients, building cohort) and center 2 (51 patients, validation cohort) were retrospectively included. Ninety-one percent of patients were ASA-PS 1-2. Overall postoperative morbidity was 23% and severe morbidity 12%. The area under the receiver operating characteristic curve of CT-PS score was 0.968 (95% CI: 0.901-1.000) in the building cohort and 0.828 (95% CI: 0.693-0.963) in the validation cohort. The optimal thresholds yielded 87% (95% CI: 83-91%) sensitivity and 100% (95% CI: 91-100%) specificity in the building cohort and 75% (95% CI: 69-81%) sensitivity and 83% (95% CI: 77-88%) specificity in the validation cohort for the prediction of ASA-PS.

Conclusion: Preoperative chest-abdomen-pelvis CT thoroughly and wisely read is highly accurate to differentiate patients with ASA-PS I/II from those with ASA-PS III/IV before left colectomy.