Can Ambulatory Blood Pressure Monitoring Solve the Conundrum of True Cryptogenic Stroke?
Background: True Cryptogenic stroke represents a real mysterious event for both neurologists and cardiologists. In some cases, exhausting all available investigations may fail to prove the thrombo-embolic theory. Ambulatory arterial stiffness index (AASI) is a new non-invasive index, calculated from ambulatory blood pressure monitoring (ABPM) and can measure the arterial stiffness easily.
Hypothesis: We tried to use the non-invasive parameter of vascular stiffness; AASI, to support our hypothesis of possible vascular background of true CS rather than thrombo-embolic theory.
Methods: we recruited 49 patients with stroke who proved by extensive work-up as being cryptogenic (Group I). We excluded all known risk factors for stroke and we added other 24 cases as control group (Group II). ABPM and calculation of ASSI for all was done.
Results: Concerning AASI, it was 0.57 ± 0.02 in-group I while it was 0.51 ± 0.03 in-group II. This difference was highly significant (t=- 8.92, p<0.001). On plotting the ROC curve, it was clear that AASI is a strong predictor of occurrence of cryptogenic stroke (CS) in our patients with cutoff point=0.53, p<0.001, area under the curve AUC= 0.89, Sensitivity=96%, specificity=84%.
Conclusion: AASI; a measure of the dynamic relation between diastolic and systolic blood pressure throughout the whole day, seems to be a good predictor for occurrence of true CS and support our theory of vascular rather than thrombo-embolic event. In future, this can support the addition of ABPM and calculation of AASI in routine clinical practice in patients with true CS.