Prognostic Significance of Raised Cardiac Troponin T in Patients Presenting with Acute Limb Ischaemia

Objective

To study the relation between serum cardiac troponin T (cTnT) and mortality in patients presenting with acute limb ischaemia secondary to an embolism.

Material and methods

A two years prospective study of all patients admitted to the vascular unit with a diagnosis of acute limb ischaemia secondary to an embolism. On admission all patients had an ECG. A blood sample was taken for measurement of cTnT, CRP, serum biochemistry, full blood count and clotting. All embolectomies were performed under local anaesthesia. Patients were followed until discharge from hospital and up to twelve months after surgery.

Results

There were 37 patients with lower limb and 2 patients with upper limb ischaemia. Twenty four patients were female and fifteen were male, with the mean age of 76 years (50–95) for women and 84 years (77–90) for men. Seventeen patients (44%) had a raised cTnT. The patients with raised cTnT were older than those with normal cTnT [86y (77–92) vs 77y (51–95), p=0.01, t test]. The mean cTnT was 0.20μg/L (range: 0.11–0.27). Only two patients with raised cTnT gave a history of chest pains. All of the patients with an elevated cTnT had also raised CRP. There was no significant difference in the serum creatinine in the group of patients with elevated cTnT compared to those with normal cTnT [112μmol/L (range 98–159) vs 119μmol/L (range: 47–177), p=ns]. The cumulative survival for cTnT+ patients at 7 days was 53% and that of cTnT− patients was 100%. The cumulative survival for cTnT+ and cTnT− patients was statistically different (p=0.0000, χ²=13.1, Log Rank test). Using regression analysis, an elevated cTnT was found to be an independent predictor of outcome.

Conclusion

A significant proportion of patients presenting with an acutely ischaemic limb have an elevated cTnT. An elevated cTnT may be an early marker of overall disease severity and a predictor of outcome.

Keywords: Cardiac Troponin T, Prognostic significance, Acute limb ischaemia