Preoperative detection and management of immune heparin-induced thrombocytopenia in patients undergoing heart surgery with iloprost

OBJECTIVE: The objective of this study was to evaluate our protocol for the identification and management of patients with immune heparin-induced thrombocytopenia undergoing cardiac surgery. METHODS: Among 1518 patients who underwent cardiac surgery between June 1998 and May 2001, 32 (2.1%) presented with platelet counts less than 150,000/mm3 preoperatively or a history of prolonged (>3 days) intravenous exposure to heparin or both. These 32 patients were evaluated with an enzyme-linked immunosorbent assay for antibodies against heparin-platelet factor 4 complex. Platelets of patients with detected antibodies were tested with the prostacyclin analog iloprost for inhibition of heparin aggregation and determination of the inhibiting concentration and corresponding intravenous infusion rate of iloprost. Patients with antibodies received heparin after complete platelet inhibition with iloprost infusion. Hypotension was prevented or treated with intravenous noradrenaline. Ten randomly selected patients with similar preoperative characteristics, no previous extended exposure to heparin, and normal platelet counts served as controls. RESULTS: Ten of the 32 patients (group A, 31.3%) and none of the controls had antibodies against heparin-platelet factor 4 complex. Patients in group A underwent surgery with iloprost (6-24 ng.kg(-1).min(-1)) and had their blood pressure maintained at greater than 95 mm Hg with norepinephrine infusion (1-4 microg.kg(-1).min(-1)). Operative mortality was zero. There were no thrombotic complications or bleeding requiring exploration. One patient in group A bled 1310 mL/6 hours but did not need exploration. There was no difference in postoperative blood loss and morbidity between groups. Platelet counts were reduced by 12.5% +/- 8.7% (group A) and 38.1% +/- 15.2% (control) (P <.001) 1 hour postoperatively and reached preoperative values by the fifth postoperative day. CONCLUSIONS: Immune heparin-induced thrombocytopenia can be detected preoperatively among patients with a low platelet count or a history of prolonged heparin exposure or both. Cardiac surgery can be safely undertaken using iloprost-induced platelet inhibition during heparinization.     

Polycystins and mechanotransduction: From physiology to disease

Polycystins are key mechanosensor proteins able to respond to mechanical forces of external or internal origin. They are widely expressed in primary cilium and plasma membrane of several cell types including kidney, vascular endothelial and smooth muscle cells,osteoblasts and cardiac myocytes modulating their physiology. Interaction of polycystins with diverse ion channels, cell-cell and cell-extracellular matrix junctional proteins implicates them in the regulation of cell structure, mechanical force transmission and mechanotransduction. Their intracellular localization in endoplasmic reticulum further regulates subcellular trafficking and calcium homeostasis, finely-tuning overall cellular mechanosensitivity. Aberrant expression or genetic alterations of polycystins lead to severe structural and mechanosensing abnormalities including cyst formation, deregulated flow sensing, aneurysms,defective bone development and cancer progression,highlighting their vital role in human physiology.     

In vitro activity of tigecycline against multiple-drug-resistant, including pan-resistant, gram-negative and gram-positive clinical isolates from Greek hospitals

The in vitro activities of tigecycline and selected antimicrobials were evaluated against a variety of multiple-drug-resistant clinical isolates, including extended-spectrum beta-lactamase- and/or metallo-beta-lactamase-producing gram-negative strains, colistin-resistant strains, vancomycin- and/or linezolid-resistant enterococci, and methicillin-resistant Staphylococcus aureus (MRSA). Tigecycline showed excellent activity against a collection of difficult-to-treat pathogens currently encountered in the hospital setting.     

24‐hour aortic blood pressure variability showed a stronger association with carotid damage than 24‐hour brachial blood pressure variability: The SAFAR study

We aim to compare 24‐hour aortic blood pressure variability (BPV) with brachial BPV in relation to carotid damage as estimated by carotid intima‐media thickness (CIMT) and cross‐sectional area (CCSA). Four hundred and forty five individuals received brachial and aortic 24‐hour ambulatory BP monitoring with a validated device (Mobil‐O‐Graph). Systolic BPV was estimated by average real variability (ARV) and time‐weighted standard deviation (wSD). In multiple logistic regression analysis, CIMT > 900 μm was significantly and independently associated with aortic ARV (OR = 1.38; 95% CI: 1.04‐1.84), aortic wSD (OR = 1.65; 95% CI: 1.19‐2.29) and brachial ARV (OR = 1.53; 95% CI: 1.07‐2.18), but not with brachial wSD. CCSA > 90th percentile was significantly and independently associated with aortic ARV (OR = 1.50; 95% CI: 1.07‐2.10) and wSD (OR = 1.70; 95% CI: 1.12‐2.56), but not with brachial BPVs. In receiver operator characteristics curve analysis, aortic wSD identified CCSA > 90th percentile better than brachial wSD (AUC: 0.73 vs 0.68, P < .01). In conclusion, aortic 24‐hour systolic BPV showed a slightly stronger association with carotid damage than brachial BPV.     

Can validated wrist devices with position sensors replace arm devices for self-home blood pressure monitoring? A randomized crossover trial using ambulatory monitoring as reference

BACKGROUND: Electronic devices that measure blood pressure (BP) at the arm level are regarded as more accurate than wrist devices and are preferred for home BP (HBP) monitoring. Recently, wrist devices with position sensors have been successfully validated using established protocols. This study assessed whether HBP values measured with validated wrist devices are sufficiently reliable to be used for making patient-related decisions in clinical practice. METHODS: This randomized crossover study compared HBP measurements taken using validated wrist devices (wrist-HBP, Omron R7 with position sensor) with those taken using arm devices (arm-HBP, Omron 705IT), and also with measurements of awake ambulatory BP (ABP, SpaceLabs), in 79 subjects (36 men and 43 women) with hypertension. The mean age of the study population was 56.7 +/- 11.8 years, and 33 of the subjects were not under treatment for hypertension. RESULTS: The average arm-HBP was higher than the average wrist-HBP (mean difference, systolic 5.2 +/- 9.1 mm Hg, P < 0.001, and diastolic 2.2 +/- 6.7, P < 0.01). Twenty-seven subjects (34%) had a > or =10 mm Hg difference between systolic wrist-HBP and arm-HBP and twelve subjects (15%) showed similar levels of disparity in diastolic HBP readings. Strong correlations were found between arm-HBP and wrist-HBP (r 0.74/0.74, systolic/diastolic, P < 0.0001). However, ABP was more strongly correlated with arm-HBP (r 0.73/0.76) than with wrist-HBP (0.55/0.69). The wrist-arm HBP difference was associated with systolic ABP (r 0.34) and pulse pressure (r 0.29), but not with diastolic ABP, sex, age, arm circumference, and wrist circumference. CONCLUSIONS: There might be important differences in HBP measured using validated wrist devices with position sensor vs. arm devices, and these could impact decisions relating to the patient in clinical practice.Measurements taken using arm devices are more closely related to ABP values than those recorded by wrist devices. More research is needed before recommending the widespread use of wrist monitors in clinical practice.American Journal of Hypertension doi:10.1038/ajh.2008.176American Journal of Hypertension (2008); 21, 7, 753-758. doi:10.1038/ajh.2008.176.     

Automated device that complies with current guidelines for office blood pressure measurement: design and pilot application study of the Microlife WatchBP Office device

OBJECTIVE: Current guidelines for office blood pressure (BP) measurement recommend mercury devices, both arms measurement in the initial assessment and at least duplicate measurements at follow-up visits. This study presents the design and a pilot application study of an automated device that fulfils American, European, and International guidelines for office BP measurement. DESIGN AND FUNCTIONS: The Microlife WatchBP Office is a professional electronic mercury-free device with three function modes designed for: (a) initial assessment: triplicate automated simultaneous oscillometric both arms measurement at 60-s intervals and when there is a consistent interarm difference more than 20 mmHg systolic and/or more than 10 mmHg diastolic, the arm with the higher BP is indicated. (b) Follow-up assessment: triplicate automated oscillometric single arm measurements at 60-s intervals and their average is displayed. (c) Auscultatory measurement: by an observer using a stethoscope and a digital countdown BP display for patients with arrhythmias and other individuals in whom the oscillometric measurement is not accurate. PILOT APPLICATION STUDY: The 'initial assessment' mode was applied by three physicians in 63 patients (189 readings). Average interarm systolic BP difference was 0.04+/-5.1 mmHg and diastolic 0.4+/-3.2 mmHg. A value more than 10 mmHg interarm difference in nine systolic BP readings (5%) and three (2%) diastolic. No patient had a consistent interarm difference more than 10 mmHg in all three or two of the three readings. CONCLUSION: The Microlife WatchBP Office professional device fulfils current international requirements for office BP measurement and seems to overcome several limitations of this method when applied in clinical practice.