Brain Stress Test for Assessing Risk for Hemodynamic Stroke.

BACKGROUND: In patients with intracranial steno-occlusive disease (SOD), the risk of hemodynamic stroke depends on the poststenotic vasodilatory reserve. Cerebrovascular reactivity (CVR) is a test for vasodilatory reserve. We tested for vasodilatory reserve by using PETCO2 as the stressor, and Blood Oxygen Level Dependent (BOLD) MRI as a surrogate of blood flow. We correlate the CVR to the incidence of stroke after a 1-year follow-up in patients with symptomatic intracranial SOD. METHODS: In this retrospective study, 100 consecutive patients with symptomatic intracranial SOD that had undergone CVR testing were identified. CVR was measured as % BOLD MR signal intensity/mmHg PETCO2. All patients with normal CVR were treated with optimal medical therapy; those with abnormal CVR were offered revascularization where feasible. We determined the incidence of stroke at 1 year. RESULTS: 83 patients were included in the study. CVR was normal in 14 patients and impaired in 69 patients ipsilateral to the lesion. Of these, 53 underwent surgical revascularization. CVR and symptoms improved in 86% of the latter. The overall incidence of stroke was 4.8 % (4/83). All strokes occurred in patients with impaired CVR (4/69; 2/53 in the surgical group, all in the nonrevascularized hemisphere), and none in patients with normal CVR (0/14). CONCLUSION: Our study confirms that CO2-BOLD MRI CVR can be used as a brain stress test for the assessment of cerebrovascular reserve. Impaired CVR is associated with a higher incidence of stroke and normal CVR despite significant stenosis is associated with a low risk for stroke.

Beyond the medals: a cross-sectional study exploring retired elite female athletes' health.

Objectives: Little is known about the impact of elite sport participation on long-term athlete health. We aimed to: (1) describe musculoskeletal, mental health, reproductive/endocrine and cardiovascular characteristics in retired elite female athletes and compare to the general population and (2) explore athletes' perceptions of their elite sport participation and its impact on health. Methods: A 136-item online questionnaire was disseminated to Canadian elite female rowing and rugby athletes >18 years old, >2 years retired from elite competition. Matched general population data were obtained from Statistics Canada when available. Results: Seventy-four (24% response rate) athletes (average age 45 (±9) years; retired 15 (±9) years) completed the questionnaire (30 rowing, 44 rugby athletes). During their career, 63 athletes (85%) experienced a hip/groin, knee, foot/ankle injury, or low back pain, with 42 (67%) reporting ongoing symptoms. Athletes 35-54 years reported worse knee symptoms and quality of life compared with the general population (symptom: p=0.197; d=1.15 [0.66, 1.63]; quality of life: p=0.312 d=1.03 [0.54, 1.51]) while other hip, knee and foot/ankle outcome scores were similar. Retired athletes had lower odds of anxiety (OR=0.155 [95% CI0.062 to 0.384]), greater lifetime/ever odds of amenorrhea (OR=6.10 [95%CI 2.67 to 13.96]) and gave birth when older (p<0.05). Fifty-nine (79%) recalled witnessing or experiencing at least one form of harassment/abuse during their career. Sixty athletes (81%) rated their current health as above average or excellent and 61 (82%) would compete at the same level again if given the choice. Conclusion: These novel insights can inform future preventative efforts to promote positive elite sport-related outcomes for current, former and future female athletes.

Obesity, Type-2 Diabetes and Cancer: Mechanistic Insights.

Obesity leads to many diseases including hypercholesterolemia, type-2 diabetes, hypertension, cardiovascular disease, and cancer. It is the fastest-growing lethal disease in the Western and developing countries. The link between obesity and cancer is relatively underappreciated among the general population. Obesity represents the number one risk factor for type-2 diabetes and a considerable body of epidemiological studies supports the relationship between type-2 diabetes and many cancers. In this review, we examine the obesity-type-2-diabetes-cancer relationships from a mechanistic perspective, and where appropriate, we highlight potential pharmaceutical and dietary interventions.

Long-term changes in cerebrovascular reactivity following EC-IC bypass for intracranial steno-occlusive disease.

The purpose of this retrospective observational study is to investigate the long-term changes in cerebrovascular reactivity (CVR) as a measure of cerebral hemodynamics in patients with intracranial steno-occlusive disease (IC-SOD) after they have undergone an Extracranial-intracranial (EC-IC) bypass. Twenty-six patients suffering from IC-SOD were selected from our CVR database. Nineteen patients underwent unilateral and 7 underwent bilateral revascularization. CVR measurements were done using BOLD-MRI and precisely controlled CO2 and expressed as ΔBOLD (%)/Δ PETCO2 (mmHg). Trends in CVR over time were compared in both vascularized and non-vascularized hemispheres. Repeated measures analysis of variance with Greenhouse-Geisser correction was used to determine CVR changes within the grey matter MCA for longitudinal assessments. Overall, re-vascularized hemisphere showed a significant increase in CVR at the first follow-up, followed by a slight decrease at the second follow-up that significantly increased compared to the pre-bypass. However, the changes in the postoperative CVR were quite variable across the patients. Similar variability was seen in subsequent follow-ups, with a slight overall decline in the long term CVR as compared with first post-operative CVR. Our study demonstrates that EC-IC bypass has a beneficial long-term effect on cerebral hemodynamics and this effect varies between patients probably due to the variability in the underlying vascular pattern receiving the bypass. Hence, in the postoperative follow-up of patients routine functional imaging to monitor cerebral hemodynamics may be useful as the risk of stroke and cognitive decline remain present with impaired CVR.

Importance of Collateralization in Patients With Large Artery Intracranial Occlusive Disease: Long-Term Longitudinal Assessment of Cerebral Hemodynamic Function.

Patients with large artery intracranial occlusive disease (LAICOD) are at risk for both acute ischemia and chronic hypoperfusion. Collateral circulation plays an important role in prognosis, and imaging plays an essential role in diagnosis, treatment planning, and prognosis of patients with LAICOD. In addition to standard structural imaging, assessment of cerebral hemodynamic function is important to determine the adequacy of collateral supply. Among the currently available methods of assessment of cerebral hemodynamic function, measurement of cerebrovascular reactivity (CVR) using blood oxygen level-dependent (BOLD) MRI and precisely controlled CO2 has shown to be a safe, reliable, reproducible, and clinically useful method for long-term assessment of patients. Here, we report a case of long-term follow-up in a 28-year-old Caucasian female presented to the neurology clinic with a history of TIAs and LAICOD of the right middle cerebral artery (MCA). Initial structural MRI showed a right MCA stenosis and a small right coronal radiate lacunar infarct. Her CVR study showed a large area of impaired CVR with a paradoxical decrease in BOLD signal with hypercapnia involving the right MCA territory indicating intracerebral steal. The patient was managed medically with anticoagulant and antiplatelet therapy and was followed-up for over 9 years with both structural and functional imaging. Cortical thickness (CT) measures were longitudinally assessed from a region of interest that was applied to subsequent time points in the cortical region exhibiting steal physiology and in the same region of the contralateral healthy hemisphere. In the long-term follow-up, the patient exhibited improvement in her CVR as demonstrated by the development of collaterals with negligible changes to CT. Management of patients with LAICOD remains challenging since no revascularization strategies have shown efficacy except in patients with moyamoya disease. Management is well defined for acute ischemia where the presence and the adequacy of the collateralization dictate the need for intervention. Long-term assessment in neurovascular uncoupling (i.e., chronic ischemia) may reveal improvements in CVR as the durability of compensatory collaterals improve, even in cases with no intervention. Thus, assessment of cerebrovascular hemodynamics using CVR measurements coupled with time-of-flight MR angiography can be useful in the clinical management of patients with LAICOD.