The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

BACKGROUND

The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications.

METHODS

ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery.

RESULTS

The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784.

CONCLUSIONS

This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance.

CLINICAL TRIAL REGISTRATION

NCT03044899.

[The treatment of lower limb varices by stripping and cross sectioning of the saphenous vein at the National Hospital of Niamey: 31 operated limbs]

OBJECTIVE

The authors reported the results of surgical procedure of lower limbs varicose (LLV) by stripping and crossectomy of saphenous vein at the National hospital of Niamey.

METHODS

It is a prospective study during 5 years and half from January 2001 to June 2006. It concerned the all the patients with LLV who underwent a stripping-crossectomy of the great saphenous vein (GVS) and short saphenous vein (SSV) and elastic stocking. The anaes's clinical classification is used.

RESULTS

The series included 27 patients (31 limbs): 20 males and 7 females (Ratio: 2.8). The average age was 32.4 years (ranged: 21 to 58 years). The mean duration of symptoms was 4.2 years (ranged: 3 to 12 years). According the ANAES's classification we found 63% of patients in stage B, and 37% in stage C. We performed 35 stripping crossectomy (28 for GSV and 7 for SSV) with avulsions accessory veins in 6 cases (14%), incompetent perforator ligature in 2 cases (4.6%) and complementary sclerotherapy in 19 cases (61.3%). The postoperative complications including haematomas (9.7%), wound infections (6.5%) and paraesthesia of saphenous nerve (6.5%) were subsequently resolved with treatment. The mean duration of hospitalization was 11 days (ranged: 4 to 18 days). After a mean follow-up period of 3 years (ranged: 6 months to 6 years) the recurrent varices rate was 6.5% (2 cases) due to leg perforators in 1 case/2 and 4 cases (9.7%) of residual ankle oedema.

CONCLUSION

The LLV concerned young people. The results were good and recurrent rate is low after stripping and crossectomy for varicose stage B and C according ANAES's classification. The surgical procedure needed minute clinical and paraclinical assessment.