2 Minute Medicine Rewind February 24, 2025

Post-exercise differential response of central and brachial blood pressure in patients with coronary artery disease: A randomized crossover trial

1. Coronary artery disease patients had sustained elevations in central systolic blood pressure (cSBP) during recovery after exercise whereas controls had a hypotensive central response

2. There were no meaningful changes in brachial systolic blood pressure following exercise

3. Post-exercise cSBP response in CAD patients were present regardless of exercise intensity

Evidence Rating Level: 1 (Excellent)

This randomized controlled investigated the divergent post-exercise responses of central (cSBP) and brachial systolic blood pressure (bSBP) in patients with coronary artery disease (CAD). Given that cSBP is more predictive of cardiovascular events than bSBP and that post-exercise hypotension (PEH) is often attenuated in CAD patients, the study aimed to clarify how combined exercise of varying intensities (high vs. moderate) affects both central and peripheral BP. Seventeen patients with stable CAD and 18 age-matched controls underwent two combined exercise sessions, with post-exercise BP and arterial stiffness (cfPWV) measured at 5, 15, and 30 minutes. Linear mixed models were used for group comparisons, and individual BP responsiveness was analyzed via Bayesian methods (ROPE + HDI). There was a significant group-by-time interaction for cSBP (p < 0.001, ω² = 0.16), with CAD patients experiencing sustained elevations in cSBP during recovery (mean increase at 30 minutes: +10 mmHg, 95% CI: 4 to 17 mmHg, p = 0.001). In contrast, controls exhibited a clear central hypotensive response (mean decrease at 30 minutes: -13 mmHg, 95% CI: -19 to -7 mmHg, p = 0.003). Interestingly, bSBP did not show meaningful post-exercise changes in either group, suggesting a disconnect between central and peripheral BP responses. Individual-level analysis supported these trends, with most CAD patients (65% after high-intensity, 53% after moderate-intensity exercise) classified as central hypertensive responders, while 61% of controls demonstrated central hypotension post-exercise. Therefore, post-exercise cSBP responses in CAD patients remain elevated irrespective of exercise intensity, challenging the traditional reliance on bSBP to assess vascular response to exercise. These findings highlight the clinical importance of monitoring central BP in CAD patients, as sustained elevations in cSBP may indicate transient organ damage risk and altered hemodynamic regulation. Further research is warranted to explore whether these central BP patterns predict future cardiovascular events and how exercise interventions might be tailored to mitigate this risk.

Effect of using home-based dynamic intermittent pneumatic compression therapy during periods of physical activity on functional and vascular health outcomes in chronic stroke: A randomized controlled clinical trial

1. In individuals with chronic stroke, intermittent pneumatic compression (IPC) therapy improved performance in some functional tests and reduced central and peripheral systolic blood pressure

2. IPC therapy also increased weekly physical activity time and reduced sedentary time

Evidence Rating Level: 1 (Excellent) 

This randomized controlled trial explored the effects of home-based intermittent pneumatic compression (IPC) therapy on functional and vascular health outcomes in individuals with chronic stroke. Stroke often leads to long-term disability, with many survivors experiencing gait impairments and vascular dysfunction. IPC, typically used to prevent deep vein thrombosis, may enhance blood flow, exercise capacity, and mobility by increasing venous return. Thirty-one participants (~4 years post-stroke, mean age: 64.3 years) were randomized to a 12-week IPC program using the GMOVE Suit or a control (CON) group following usual care. Functional outcomes included the 6-minute walk test (6MWT), timed-up-and-go (TUG), and 10m walk test. Vascular health was assessed through pulse wave analysis (PWA) and carotid-femoral pulse wave velocity (cfPWV). The IPC group showed significant gains in 6MWT distance (+12%, 188m vs. 167m in CON; p < 0.05), but no changes in TUG or other functional tests. They also had reduced peripheral systolic blood pressure (136.2 mmHg vs. 142.2 mmHg; p < 0.05) and central SBP (124.4 mmHg vs. 130.4 mmHg; p < 0.05). Weekly physical activity increased by ~37%, while sedentary time fell by ~18%. Despite these benefits, cfPWV and augmentation index (AIx) remained unchanged. Further studies should explore whether higher-intensity IPC improves vascular outcomes long-term.

Maternal Overweight and Obesity and Risk of Perinatal Ischemic Stroke

1. There is a dose-response relationship between maternal BMI and PIS risk

Evidence Rating Level: 2 (Good) 

This nationwide cohort study investigated the association between maternal early pregnancy body mass index (BMI) and the risk of perinatal ischemic stroke (PIS) in infants. Perinatal ischemic stroke, occurring from 20 weeks’ gestation to 28 days post-birth, affects approximately 1 in 3,000 term-born infants and is associated with significant neurodevelopmental consequences. Given the rising prevalence of maternal obesity and its link to obstetric complications, this study aimed to clarify whether maternal overweight and obesity increase the risk of PIS. The study included 2,140,852 singleton births in Sweden from 1998 to 2019, with 415 infants diagnosed with PIS. Maternal BMI was categorized per WHO criteria: normal weight (18.5–24.9), overweight (25–29.9), and obesity classes I (30–34.9), II (35–39.9), and III (≥40). Adjusted rate ratios (aRRs) for PIS were calculated using Poisson log-linear regression. There was a dose-response relationship between maternal BMI and PIS risk. Compared to infants of normal-weight mothers (19/100,000 births), PIS rates rose to 22/100,000 for overweight mothers, 35/100,000 for obesity class II, and 40/100,000 for class III. The aRRs for PIS were 1.16 (95% CI 0.91–1.46) for overweight, 1.82 (95% CI 1.34–2.44) for obesity class I, and 1.96 (95% CI 1.27–2.91) for obesity classes II-III. These findings suggest maternal obesity is an independent risk factor for PIS, increasing risk nearly twofold in severe obesity. The study demonstrates the importance of maternal weight management and highlights the need for targeted prenatal care strategies to mitigate PIS risk. Further research should explore underlying mechanisms, including placental dysfunction and inflammation.

Association of Smoking and Young Cryptogenic Ischemic Stroke: A Case-Control Study

1. Smoking had a strong association with young cryptogenic ischemic stroke that was more pronounced in men and peaked in the 45-49 age group

2. Smoking greater than 20 pack years was necessary to see an association after adjusting for confounding variables

Evidence Rating Level: 2 (Good) 

This multicenter case-control study examined the association between smoking and cryptogenic ischemic stroke (CIS) in young adults aged 18–49, using data from the SECRETO study. As CIS accounts for up to 28% of strokes in this age group and smoking is a modifiable vascular risk factor, the study aimed to clarify smoking’s role in young CIS incidence. A total of 546 young patients with CIS (47.3% female) and 546 age- and sex-matched controls were analyzed. Smoking status and intensity (pack years) were assessed through standardized questionnaires, and conditional logistic regression adjusted for education level and vascular risk factors (hypertension, diabetes, obesity, alcohol use, etc.) was used. There was a strong association between smoking and young CIS (adjusted OR 2.39, 95% CI 1.65–3.47). The risk was more pronounced in men (OR 3.34) than women (OR 1.65) and peaked in the 45–49 age group (OR 3.77). Heavy smoking (>20 pack years) showed the strongest link to CIS (OR 4.30), especially in men (OR 6.97). Notably, no significant association emerged in women or those smoking fewer than 20 pack years after adjusting for confounders. These findings highlight smoking as an independent risk factor for young CIS, with risk intensifying with smoking intensity and age, particularly among men. The study underscores the need for targeted smoking cessation strategies and more research into sex-specific mechanisms underlying CIS.

Association between levothyroxine supplementation for hypothyroidism in late pregnancy and risk of prematurity: a population-based cohort study

1. Levothyroxine usage for hypothyroidism in pregnancy was not linked to elevated prematurity risk

Evidence Rating Level: 2 (Good)

While untreated hypothyroidism is linked to obstetrical complications, including prematurity, the impact of levothyroxine therapy during late gestation remains unclear. This population-based cohort study aimed to see if levothyroxine supplementation in late pregnancy affects the risk of prematurity. 9,489 pregnancies with hypothyroidism from the Quebec Pregnancy Cohort (1998–2015). Of these, 70.3% received levothyroxine during the final two months of pregnancy. Prematurity was defined as delivery before 37 weeks of gestation. The study assessed levothyroxine exposure (yes/no), duration (>30 days), cumulative dose (>7125 mcg), and mean daily dose (>125 mcg/day). Additionally, dosage variations after the second trimester were examined. There was no significant association between levothyroxine use and prematurity risk (adjusted RR 0.98; 95% CI 0.81–1.20). Neither longer exposure (aRR 0.99; 95% CI 0.81–1.21) nor higher cumulative (aRR 0.97; 95% CI 0.73–1.27) or daily doses (aRR 0.95; 95% CI 0.72–1.26) influenced prematurity risk. Increasing the levothyroxine dose after the second trimester also showed no effect (aRR 0.84; 95% CI 0.67–1.05), though a 30% or less dose increase was linked to a 28% reduced prematurity risk (aRR 0.72; 95% CI 0.54–0.96). These findings suggest levothyroxine supplementation in late pregnancy is safe and does not elevate prematurity risk. The observed reduced risk with modest dosage increases may reflect better management of hypothyroidism. This study supports current guidelines endorsing levothyroxine use during pregnancy and highlights the need for further research into the complex interplay between thyroid function and prematurity.

Image: PD

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