Vasomotor reactivity has been identified as a prognostic marker for cerebrovascular damage. It is measured using TCD, which allows continuous monitoring and assessment of the intracranial circulation with each heartbeat providing physiologic information. Basis of vasomotor reactivity is the ability of vessel to dilatate in response to increased blood CO2 content. Typical use of vasomotor reactivity has been associated with the assessment for the risk of perioperative stroke during cardiopulmonary bypass and during other major surgeries, during other procedures with hypotension risk and for the stroke risk stratification from asymptomatic carotid stenosis.
Vasomotor reactivity has been measured within the population-based Rotterdam Study, but no association between vasomotor reactivity and stroke was found. This impressive, population based study aimed to assess whether impaired cerebral vasomotor reactivity has associates with poorer survival and all-cause mortality, cardiovascular mortality, non-cardiovascular mortality, and stroke in a general elderly population. From 1997-1999, 2732 patients underwent vasomotor reactivity assessment. Follow up was completed January 2011. The associations with both all-cause mortality and cardiovascular mortality remained significant after censoring for incident stroke suggest that a low vasomotor reactivity is a marker of accumulating vascular damage. The main causes of cardiovascular death after censoring for strokes were heart failure, cardiac arrest, sudden death with unknown cause, and myocardial infarction which supports the hypothesis that loss of cerebral vasomotor reactivity is a reflection of a more systemic dysfunction of the vascular system rather than only cerebrovascular damage.
Our world faces increase in the vascular disease. The authors spotlight identification of parameters predictive of such burden using non-invasive measurement of hemodynamic change when cerebral-vascular circulation is challenged. I commend the authors on these efforts, impressive recruitment and follow up. However, as an RVT who knows limitations of TCD well, I don’t foresee its use in prognosis or clinical management of the conditions where association was established.