Chi-Lun Huang

The application of infrared thermography in evaluation of patients at high risk for lower extremity peripheral arterial disease

OBJECTIVE We investigated the usefulness of infrared thermography in evaluating patients at high risk for lower extremity peripheral arterial disease (PAD), including severity, functional capacity, and quality of life. METHODS A total of 51 patients (23 males; age 70 ± 9.8 years) were recruited. They completed three PAD-associated questionnaires, including walking impairment, vascular quality of life, and 7-day physical activity recall questionnaires before a 6-minute walking test (6MWT). Ankle-brachial index (ABI) and segmental pressure were analyzed for PAD diagnosis and stenotic level assessment. The cutaneous temperature at shin and sole were recorded by infrared thermography before and after the walk test. Detailed demographic information and medication list were obtained. RESULTS Twenty-eight subjects had abnormal ABI (ABI <1), while PAD was diagnosed in 20. No subjects had non-compressible artery (ABI >1.3). Demographic profiles and clinical parameters in PAD and non-PAD patients were similar, except for age, smoking history, and hyperlipidemia. PAD patients walked shorter distances (356 ± 102 m vs 218 ± 92 m; P < .001). Claudication occurred in 14 patients, while seven failed in completing the 6MWT. The rest temperatures were similar in PAD and non-PAD patients. However, the post-exercise temperature dropped in the lower extremities with arterial stenosis, but was maintained or elevated slightly in the extremities with patent arteries (temperature changes at sole in PAD vs non-PAD patients: -1.25 vs -0.15°C; P < .001). The exercise-induced temperature changes at the sole were not only positively correlated with the 6MWD (Spearman correlation coefficient = 0.31, P = .03), but was also correlated with ABI (Spearman correlation coefficient = 0.48, P < .001) and 7-day physical activity recall scores (Spearman correlation coefficient = 0.30, P = .033). CONCLUSION By detecting cutaneous temperature changes in the lower extremities, infrared thermography offers another non-invasive, contrast-free option in PAD evaluation and functional assessment.

Usefulness of Paradoxical Systolic Blood Pressure Increase After Exercise as a Predictor of Cardiovascular Mortality

Exercise treadmill testing (ETT) is a well-accepted examination for patients with suspected coronary artery disease (CAD), and exercise induced ST-segment deviation is commonly used for CAD detection. However, recent evidence shows that systolic blood pressure (SBP) changes during and after exercise were associated with CAD severity, risk of acute myocardial infarction and stroke, new-onset hypertension, and even cardiovascular mortality. We retrospectively assessed 3,054 patients referred for ETT in 1996. Blood pressure and heart rate were recorded at rest, during peak exercise, and 1 and 3 min after exercise. SBP at 3 min of recovery equal to or higher than that at 1-min of recovery was defined as paradoxical SBP increase. These patients were categorized into 4 groups according to ETT ST-segment change and postexercise SBP change. After 10 years of follow-up, 346 patients (11%) died, with 129 (4%) dying from cardiovascular disease (CVD). Among the 4 groups, patients with ischemic ST-segment change and paradoxical SBP increase were associated with a higher risk for mortality, with odds ratios of 1.86 (95% confidence interval 1.31 to 2.65) for all-cause mortality and 3.18 (95% confidence interval 1.94 to 5.20) for CVD mortality, respectively. Patients with isolated paradoxical SBP increase still had a higher risk of CVD mortality (odds ratio 1.80, 95% confidence interval 1.70 to 3.04), even after controlling other cardiovascular risk factors. In subgroup analysis of 346 mortality subjects, patients with ischemic ST-segment change and paradoxical SBP increase would be more likely to die from CVD. In conclusion, compared with ischemic ST-segment change, paradoxical SBP increase after exercise is an important and significant predictor of CVD mortality.

Serum adipocyte fatty acid-binding protein levels in patients with critical illness are associated with insulin resistance and predict mortality

IntroductionHyperglycemia and insulin resistance are commonplace in critical illness, especially in patients with sepsis. Recently, several hormones secreted by adipose tissue have been determined to be involved in overall insulin sensitivity in metabolic syndrome-related conditions, including adipocyte fatty-acid binding protein (A-FABP). However, little is known about their roles in critical illness. On the other hand, there is evidence that several adipose tissue gene expressions change in critically ill patients.MethodsA total of 120 patients (72 with sepsis, 48 without sepsis) were studied prospectively on admission to a medical ICU and compared with 45 healthy volunteers as controls. Various laboratory parameters and metabolic and inflammatory profiles were assessed within 48 hours after admission. Clinical data were collected from medical records.ResultsCompared with healthy controls, serum A-FABP concentrations were higher in all critically ill patients, and there was a trend of higher A-FABP in patients with sepsis. In multivariate correlation analysis in all critically ill patients, the serum A-FABP concentrations were independently related to serum creatinine, fasting plasma glucose, total cholesterol, TNF-alpha, albumin, and the Acute Physiology and Chronic Health Evaluation II scores. In survival analysis, higher A-FABP levels (> 40 ng/ml) were associated with an unfavorable overall survival outcome, especially in sepsis patients.ConclusionsCritically ill patients have higher serum A-FABP concentrations. Moreover, A-FABP may potentially serve as a prognostic biomarker in critically ill patients with sepsis.

Serum Angiopoietin-Like Protein 2 Concentrations Are Independently Associated with Heart Failure

Objective Angiopoietin-like protein 2 (ANGPTL2), which is mainly expressed from adipose tissue, is demonstrated to be involved in obesity, metabolic syndrome, and atherosclerosis. Because several adipocytokines are known to be associated with heart failure (HF), here we investigated the association of ANGPTL2 and HF in Taiwanese subjects. Methods and Results A total of 170 symptomatic HF patients and 130 age- and sex-matched controls were enrolled from clinic. The echocardiography was analyzed in each patient, and stress myocardial perfusion study was performed for clinical suspicion of coronary artery disease. Detailed demographic information, medications, and biochemical data were recorded. Circulating adipocytokines, including tumor necrosis factor-alpha (TNF-α), adiponectin, adipocyte fatty acid-binding protein (A-FABP) and ANGPTL2, were analyzed. Compared with the control group subjects, serum ANGPTL2 concentrations were significantly higher in HF group patients. In correlation analyses, ANGPTL2 level was positively correlated to creatinine, fasting glucose, triglyceride, hsCRP, TNF-α, NT-proBNP and A-FABP levels, and negatively correlated with HDL-C and left ventricular ejection fraction. In multiple regression analysis, A-FABP, hsCRP, and HDL-C levels remained as independent predictors for ANGPTL2 level. To determine the association between serum ANGPTL2 concentrations and HF, multivariate logistic regression analyses were performed with subjects divided into tertiles by ANGPTL2 levels. For the subjects with ANGPTL2 levels in the highest tertile, their risk of HF was about 2.97 fold (95% CI = 1.24–7.08, P = 0.01) higher than those in the lowest tertile. Conclusion Our results demonstrate a higher circulating ANGPTL2 level in patients with HF, and the upregulating ANGPTL2 levels might be associated with metabolic derangements and inflammation.

Association between serum adipocyte fatty-acid binding protein concentrations, left ventricular function and myocardial perfusion abnormalities in patients with coronary artery disease

BackgroundAdipokines, including adipocyte fatty acid-binding protein (A-FABP), have been demonstrated to be involved in the pathogenesis of atherosclerosis. In the present study, we investigated the association of circulating A-FABP level with severity of myocardial perfusion abnormalities analyzed by Tl-201 dipyridamole single-photon emission computed tomography.MethodsA total of 170 patients with coronary artery disease (CAD) from cardiovascular clinics were enrolled in the study. Serum A-FABP levels, echocardiography, and stress myocardial perfusion imaging results were analyzed.ResultsCompared with the patients with mild CAD (summed stress score [SSS] ≤ 8), those with moderate to severe CAD (SSS > 8) had significantly higher A-FABP concentrations. However, the difference was attenuated in the subgroup of patients with heart failure. In the correlation analyses, A-FABP level was correlated with age, body mass index, waist circumference, levels of creatinine, fasting glucose, high-sensitivity C-reactive protein, N-terminal pro-brain natriuretic peptide, adiponectin, and several echocardiographic parameters, including left ventricular ejection fraction. Multivariate logistic regression analysis demonstrated that the A-FABP level was not only associated with higher SSS (odds ratio, 1.30; 95% confidence interval [CI], 1.01–1.69; P = 0.048), but also an independent risk factor for heart failure (odds ratio 2.71, 95% CI, 1.23–5.94; P = 0.013).ConclusionsSerum A-FABP levels not only were associated with myocardial perfusion abnormalities and left ventricular function, but also predicted the presence of heart failure in our patients with CAD.

Association of lower extremity arterial calcification with amputation and mortality in patients with symptomatic peripheral artery disease.

Objective The clinical implication of the coronary artery calcium score (CS) is well demonstrated. However, little is known about the association between lower extremity arterial calcification and clinical outcomes. Methods and Results Eighty-two patients with symptomatic peripheral artery disease (age 61.0±12.4 years) were followed for 21±11 months. CSs, ranging from the common iliac artery bifurcation to the ankle area, were analyzed through noncontrast multidetector computed tomography images retrospectively. The primary endpoints of this study were amputation and mortality. Old age, diabetes, hyperlipidemia, and end-stage renal disease were associated with higher CSs. Patients with more advanced Fontaine stages also tended to have significantly higher CSs (p = 0.03). During the follow-up period (21±11 months), 29 (35%) patients underwent amputation, and 24 (29%) patients died. Among the patients who underwent amputation, there were no significant differences in CSs between the amputated legs and the non-amputated legs. In the Cox proportional hazard model with CS divided into quartiles, patients with CS in the highest quartile had a 2.88-fold (95% confidence interval [CI] 1.18–12.72, p = 0.03) and a 5.16-fold (95% CI 1.13–21.61, p = 0.04) higher risk for amputation and all-cause mortality, respectively, than those with CS in the lowest quartile. These predictive effects remained after conventional risk factor adjustment. Conclusion Lower extremity arterial CSs are associated with disease severity and outcomes, including amputation and all-cause mortality, in patients with symptomatic peripheral artery disease. However, the independent predictive value needs further investigation in large scale, prospective studies.

Association of Plasma Thrombospondin-1 Level with Cardiovascular Disease and Mortality in Hemodialysis Patients

BACKGROUND Thrombospondin-1 (TSP-1) is known to be involved in the regulation of angiogenesis, inflammation, and vascular function. Clinical studies have demonstrated its correlation with peripheral artery disease, coronary artery disease, and pulmonary hypertension. In this study, we explored its potential roles in the background of end-stage renal disease (ESRD). METHODS A total of 140 ESRD outpatients (ages 61.0 ± 12.4 years) were prospectively followed for 34 ± 7 months. Their TSP-1 levels were analyzed from pre-hemodialysis blood sample. Cardiovascular survey included ankle- brachial index (ABI), echocardiography and Tl-201 dipyridamole single-photon emission computed tomography (SPECT). RESULTS Plasma TSP-1 levels were higher in those patients with preexisting clinical evidence of cardiovascular disease (CVD) than those without (p = 0.002). TSP-1 concentrations were also correlated with ABI, left ventricular ejection fraction, and scar burden in SPECT. Stepwise logistic regression analysis revealed that TSP-1 level was independently associated with the presence of CVD, with an odds ratio of 1.38 [95% confidence interval (CI), 1.09-1.75, p = 0.008]. In survival analyses, 31 patients (22%) died during the follow-up, 16 (52%) arising from cardiovascular causes. Cox hazards analysis revealed that the patients with TSP-1 levels in the highest tertile had a 5.32- and 6.75-fold higher risk for all-cause and cardiovascular mortality than those in the lowest tertile. This predictive value for all-cause mortality still persisted after multivariate adjustment (hazard ratio, 8.71; 95% CI, 1.36-55.68; p = 0.02). CONCLUSIONS This study hallmarks the association of elevated TSP-1 level with CVD and adverse outcome among hemodialysis patients. KEY WORDS Thrombospondin-1; End-stage renal disease; Cardiovascular disease; Mortality.