Resting heart rate and incident venous thromboembolism: the Multi-Ethnic Study of Atherosclerosis

Acute ischemic stroke in Tsutsugamushi: understanding the underlying mechanisms and risk factors

BACKGROUND

Tsutsugamushi (scrub typhus) is an acute infectious febrile disease common in the Asia-Pacific region. Common symptoms of tsutsugamushi include lymphadenopathy, fever, and myalgia, and it rarely causes acute ischemic stroke (AIS). However, we hypothesized that tsutsugamushi infection could trigger AIS.

METHOD

We retrospectively examined patients diagnosed with AIS within 2 weeks of tsutsugamushi diagnosis at three hospitals over a 15-year period. We categorized patients who developed AIS while being treated for tsutsugamushi as the case group and those (of similar age and sex) who did not develop AIS as the control group. The case and control groups consisted of 22 and 66 participants, respectively. When a scattered pattern was observed or lesions were found in two or more vascular territories on diffusion-weighted imaging, the pattern was defined as embolic. Other patterns were defined as nonembolic.

RESULTS

Among the 19 patients, excluding three with transient ischemic stroke, 15 (78.9%) showed an embolic pattern. Although fever was common in the control group, it was less common in the case group. A higher D-dimer level at the time of hospitalization was associated with the development of AIS in patients with tsutsugamushi.

CONCLUSIONS

AIS in patients with tsutsugamushi showed an embolic rather than a non-embolic pattern on brain magnetic resonance imaging. It was more likely to occur in patients with risk factors for stroke. Tsutsugamushi patients with AIS were likely to have no fever or high D-dimer levels. We hypothesized that D-dimers play an important role in the pathophysiology, where tsutsugamushi infection increases the likelihood of AIS.

Adipokines and incident venous thromboembolism: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Obesity leads to adipocyte hypertrophy and adipokine dysregulation and is an independent risk factor for venous thromboembolism (VTE). However, the association between adipokines and VTE is not well established.

OBJECTIVES

To examine whether adipokines are associated with increased risk of incident VTE.

METHODS

We studied 1888 participants of the Multi-Ethnic Study of Atherosclerosis cohort who were initially free of VTE and had adipokine (adiponectin, leptin, and resistin) levels measured at either examination 2 or 3 (2002-2004 or 2004-2005, respectively). During follow-ups, VTE was ascertained through hospitalization records and death certificates by using ICD-9 and 10 codes. We used multivariable Cox proportional hazards regression to assess the association between 1 standard deviation (SD) log-transformed increments in adipokines and incident VTE.

RESULTS

The mean ± SD age was 64.7 ± 9.6 years, and 49.8% of participants were women. Medians (interquartile range) of adiponectin, leptin, and resistin were 17.3 (11.8-26.2) mcg/mL, 13.5 (5.6-28.2) ng/mL, and 15.0 (11.9-19.0) ng/mL, respectively. There were 78 incident cases of VTE after a median of 9.7 (5.0-12.4) years of follow-up. After adjusting for sociodemographics, smoking, and physical activity, the hazard ratios (95% CIs) per 1 SD increment of adiponectin, leptin, and resistin were 1.14 (0.90-1.44), 1.29 (1.00-1.66), and 1.38 (1.09-1.74), respectively. The association for resistin persisted after further adjustments for body mass index and computed tomography-derived total visceral adipose tissue area.

CONCLUSION

Higher resistin levels were independently associated with greater risk of incident VTE. Larger prospective cohort studies are warranted to confirm this association.

Heart Rate Variability Impairment Is Associated with Right Ventricular Overload and Early Mortality Risk in Patients with Acute Pulmonary Embolism

The association between heart rate variability (HRV) and mortality risk of acute pulmonary embolism (APE), as well as its association with right ventricular (RV) overload is not well established. We performed an observational study on consecutive patients with confirmed APE. In the first 48 h after admission, 24 h Holter monitoring with assessment of time-domain HRV, echocardiography and NT-proBNP (N-terminal pro-B-type natriuretic peptide) measurement were performed in all participants. We pre-examined 166 patients: 32 (20%) with low risk of early mortality, 65 (40%) with intermediate-low, 65 (40%) with intermediate-high, and 4 (0.02%) in the high risk category. The last group was excluded from further analysis due to sample size, and finally, 162 patients aged 56.3 ± 18.5 years were examined. We observed significant correlations between HRV parameters and echocardiographic signs of RV overload. SDNN (standard deviation of intervals of all normal beats) correlated with echocardiography-derived RVSP (right ventricular systolic pressure; r = -0.31, p = 0.001), TAPSE (tricuspid annulus plane systolic excursion; r = 0.21, p = 0.033), IVC (inferior vena cava diameter; r = -0.27, p = 0.002) and also with NT-proBNP concentration (r = -0.30, p = 0.004). HRV indices were also associated with APE risk stratification, especially in the low-risk category (r = 0.30, p = 0.004 for SDNN). Univariate and multivariate analyses confirmed that SDNN values were associated with signs of RV overload. In conclusion, we observed a significant association between time-domain HRV parameters and echocardiographic and biochemical signs of RV overload. Impaired HRV parameters were also associated with worse a clinical risk status of APE.