Body surface area determined by whole-body CT scanning: need for new formulae?

Cerebral Oxygen Saturation Associates with Changes in Oxygen Transport Parameters during Cardiopulmonary Bypass

(1) Background: Adequate organ perfusion during cardiopulmonary bypass (CPB) requires accurate estimation and adjustment of flow rates which conventional methods may not always achieve. Perioperative monitoring of cerebral oxygen saturation (ScO2) may detect changes in oxygen transport. This study aims to compare estimated and measured perfusion flow rates and assess the capacity of ScO2 to detect subtle changes in oxygen transport during CPB. (2) Methods: This observational study included 50 patients scheduled for elective coronary artery bypass grafting (CABG) surgery, all of whom provided written informed consent. Perfusion flow rates were estimated using the DuBois formula and measured using echocardiography and a flow probe in the arterial line of the CPB system. ScO2 was continuously monitored, alongside intermittent measurements of oxygen delivery and extraction ratios. (3) Results: Significant discrepancies were found between estimated flow rates (5.2 [4.8-5.5] L/min) and those measured at the start of the surgery (4.6 [4.0-5.0] L/min). These discrepancies were flow rate-dependent, being more pronounced at lower perfusion rates and diminishing as rates increased. Furthermore, ScO2 showed a consistent correlation with both oxygen delivery (r = 0.48) and oxygen extraction ratio (r = 0.45). (4) Conclusions: This study highlights discrepancies between estimated and actual perfusion flow rates during CPB and underscores the value of ScO2 monitoring as a continuous, noninvasive tool for maintaining adequate organ perfusion, suggesting a need for improved, patient-tailored perfusion strategies.

Adaptively resettable microfluidic patch for sweat rate and electrolytes detection

Skin-interfaced microfluidic patch has become a reliable device for sweat collection and analysis. However, the intractable problems of emptying the microchannel for reuse, and the channel's volumetric capacity limited by the size of the patch, directly hinder the practical application of sweat sensors. Herein, we report an adaptively resettable microfluidic sweat patch (Art-Sweat patch) capable of continuously monitoring both sweat rate (0.2-4.0 μL min-1) and total ionic charge concentration (10-200 mmol L-1). We develop a platform with a vertical and horizontal microchannel combined strategy, enabling repeatedly filling sweat and emptying the microchannel for autonomously resetting and detecting. The variation in the emptied volume is designed to be adaptively identified by the sensor, resulting in enhanced stability and an enlarged volumetric capacity of over 300 μL. By integrating with self-designed wireless transmission modules, the proposed Art-Sweat patch shows product-level wearability and high performance in monitoring variations in regional sweat rate and concentration for hydration status assessment.

Impact of a 16-week strength training program on physical performance, body composition and cardiac remodeling in previously untrained women and men

Even if more and more women are involved in strength-training (ST) programs in fitness centers, studies on strength gain, body composition, and cardiac remodeling were mainly conducted in men and whether they are similar in women remains to be explored. In this context, the aim of our study was to assess the effect of a supervised ST program on strength gains, body composition, and cardiac remodeling in previously untrained women and men. 17 healthy and previously untrained young women and 17 young men participated in a supervised 16-week ST program built according to the recommendation of the American College of Sports Medicine in terms of intensity, and strictly using similar volume and intensity in both groups. Strength performance, body composition, and cardiac remodeling were evaluated every 4 weeks. Cardiac adaptations were assessed using resting echocardiography, including regional 2D-Strain analysis of the left atrium and ventricle (LA and LV, respectively). Despite lower values at baseline, women exhibited similar or even higher strength gains compared to men. ST induced a decrease of body and abdominal fat mass and an increase of lean body mass in both groups. Similar cardiac remodeling was observed in women, and women, including an early and progressive LV and LA enlargement throughout the ST program, without any alteration of LV diastolic and systolic functions. These findings underlie that ST programs are highly suitable for women to enhance their strength performance and their cardiovascular health.

Noninvasive electrophysiological differences between women and men: differences in body size not an explanation

There are numerous sex-related differences in cardiac electrophysiology and arrhythmia propensity but very little knowledge about the reasons. Difference in body size has been proposed as one reason and was tested in this study of >20 cardiac electrophysiology parameters in 319 (158 women) apparently healthy 50- to 64-yr-old subjects from a randomly enrolled population sample, the pilot SCAPIS (Swedish Cardiopulmonary Bioimaging Study), using Frank vectorcardiography. We studied conventional conduction intervals, parameters reflecting electrical heterogeneity (dispersion) in the ventricles, QRS- and T-vector directions, spatial QRS-T angles, and T-vector loop morphology. Body surface area (BSA; 2 methods) and lean body mass (LBM), both estimated from body weight and height, were used as body size parameters. According to multivariable linear regression analysis adjusted for sex, there was no association between electrophysiological parameters and body size apart from QRS duration and QRSarea. In conclusion, most electrophysiological parameters assessed completely noninvasively and showing statistically significant differences between women and men on the group level show no association with BSA or LBM. Scaling (indexing) the electrophysiological parameters for body size parameters is therefore not an option. Consequently, the explanation for the sex-related electrophysiological differences should be sought along other lines.NEW & NOTEWORTHY We sought explanations for sex-related differences in >20 cardiac electrophysiology parameters including conventional conduction intervals in 319 (158 women) apparently healthy 50- to 64-yr-old subjects using Frank vectorcardiography, a novelty. Our hypothesis that body size was partly explanatory for such differences had to be refuted apart from QRS duration and QRSarea. Scaling (indexing) electrophysiological parameters for body size is therefore not an option and explanations for electrophysiological sex-related differences are to be sought elsewhere.

Exposed Body Surface Area-A Determinate for UV Radiant Energy in Human UV Exposure Studies

Solar ultraviolet (UV) exposure of people and related health risk is mainly examined by estimating the received UV radiant exposure. However, for several effects such as DNA damage, vitamin D photosynthesis or the probability of developing skin cancer, UV radiant energy is important and with that the size of exposed skin area. There is also a complex interaction between body shape and behavior like sun exposure habits, so that careful analysis is necessary when estimating health effects from UV exposure. In this paper, knowledge on body shape and methods of calculating the total body surface area (BSA) are summarized. BSA depends mainly on the height and weight of a person as well as on gender, ethnicity and body shape. BSA and body shape differ significantly between different populations and both change during life. This paper proposes formulas for BSA that consider height, weight, gender, ethnicity and body shape. As the exposed BSA depends on clothing, finally an approach is presented which aims to calculate the size of body parts released by real garments. In summary, this paper will enable future researchers to quantify the exposed BSA by best matching their study population and consequently investigate risks caused by solar UV exposure.

Estimation of percent body surface area in cats with use of computed tomography

OBJECTIVE

To establish a baseline reference and create a user-friendly chart for normal body surface area (BSA) in the adult domestic cat similar to the "Rule of Nines" chart.

DESIGN

Prospective cadaveric study.

SETTING

University Teaching Hospital.

ANIMALS

Seven adult domestic short-haired feline cadavers of normal body condition (4-6/9) and body weight.

INTERVENTION

Individual whole-body computed tomography (CT) scan was performed on all cats. Images were analyzed with 3-dimensional technology to measure the BSA. A chart was created, illustrating the individual surface area of each body part.

MEASUREMENTS AND MAIN RESULTS

Obtained measurements of the cats are different from surface areas of people and dogs. Percentage of total BSA for cats was as follows: head 13%, neck 5%, thorax 20%, abdomen 15%, pelvis and tail 9%, front legs 7% each, and pelvic legs 12% each.

CONCLUSION

The distribution of BSA between body parts is different in cats compared to dogs and people. A species-specific chart was created to assure a more accurate estimation of BSA in cats.

SUVfdg: A standard-uptake-value (SUV) body habitus normalizer specific to fluorodeoxyglucose (FDG) in humans

Purpose

To devise a new body-habitus normalizer to be used in the calculation of an SUV that is specific to the PET tracer 18F-FDG.

Methods

A cohort of 481-patients was selected for analysis of 18F-FDG uptake into tissues unaffected by their disease. Among these, 65-patients had only brain concentrations measured and the remaining 416 were randomly divided into an 86-patient test set and a 330-patient training set. Within the test set, normal liver, spleen and blood measures were made. In the training set, only normal liver concentrations were measured. Using data from the training set, a simple polynomial function of height and weight was selected and optimized in a fitting procedure to predict each patient’s mean liver %ID/ml. This function, when used as a normalizer, defines a new SUV metric (SUVfdg) which we compared to SUV metrics normalized by body weight (SUVbw), lean-body mass (SUVlbm) and body surface-area (SUVbsa) in a five-fold cross-validation. SUVfdg was also evaluated in the independent brain-only and whole-body test sets.

Results

For patients of all sizes including pediatric patients, the normal range of liver 18F-FDG uptake at 60 minutes post injection in units of SUVfdg is 1.0 ± 0.16. Liver, blood, and spleen SUVfdg in all comparisons had lower coefficients of variation compared to SUVbw SUVlbm and SUVbsa. Blood had a mean SUVfdg of 0.8 ± 0.11 and showed no correlation with age, height, or weight. Brain SUVfdg measures were significantly higher (P<0.01) in pediatric patients (4.7 ± 0.9) compared to adults (3.1 ± 0.6).

Conclusion

A new SUV metric, SUVfdg, is proposed. It is hoped that SUVfdg will prove to be better at classifying tumor lesions compared to SUV metrics in current use. Other tracers may benefit from similarly tracer-specific body habitus normalizers.

Use of computed tomography to determine a species-specific formula for body surface area in bearded dragons (Pogona vitticeps)

OBJECTIVE

To use CT-derived measurements to calculate a shape constant (K constant) and create a formula to calculate body surface area (BSA) on the basis of body weight in bearded dragons (Pogona vitticeps).

ANIMALS

12 adult client-owned bearded dragons that underwent CT between December 4, 2019, and April 2, 2020.

PROCEDURES

Each bearded dragon in this prospective cohort study underwent physical examination, body weight measurement, and CT. A 3-D surface model was then reconstructed from CT data with available software and used for BSA calculations. Animals were considered collectively and grouped by sex and age. Nonlinear regression analysis of BSA versus body weight was performed, and a species-specific formula was derived for calculating BSA in bearded dragons.

RESULTS

Mean age, body weight, and CT-derived BSA were 2.1 years, 356 g, and 580 cm². The calculated K constant was 11.6 (R² = 0.994; SE = 0.275) for the 12 bearded dragons, and the CT-derived BSA formula was as follows: BSA in cm² = 11.6 × (body weight in g)^2/3. The K constant differed substantially for bearded dragons grouped by age (12.1 for younger [between 1 and ≤ 2 years of age; n = 8] vs 10.9 for older [> 2 years of age; 4] animals) but did not differ on the basis of sex.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that because the K constant for bearded dragons in the present study was larger than the preexisting K constant of 10 used for reptiles or the various K constants established for some companion mammals, doses of chemotherapeutic drugs needed to treat affected bearded dragons may be higher than previously thought.

Deep neural network for automatic volumetric segmentation of whole-body CT images for body composition assessment

BACKGROUND & AIMS

Body composition analysis on CT images is a valuable tool for sarcopenia assessment. We aimed to develop and validate a deep neural network applicable to whole-body CT images of PET-CT scan for the automatic volumetric segmentation of body composition.

METHODS

For model development, one hundred whole-body or torso ¹⁸F-fluorodeoxyglucose PET-CT scans of 100 patients were retrospectively included. Two radiologists semi-automatically labeled the following seven body components in every CT image slice, providing a total of 46,967 image slices from the 100 scans for training the 3D U-Net (training, 39,268 slices; tuning, 3116 slices; internal validation, 4583 slices): skin, bone, muscle, abdominal visceral fat, subcutaneous fat, internal organs with vessels, and central nervous system. The segmentation accuracy was assessed using reference masks from three external datasets: two Korean centers (4668 and 4796 image slices from 20 CT scans, each) and a French public dataset (3763 image slices from 24 CT scans). The 3D U-Net-driven values were clinically validated using bioelectrical impedance analysis (BIA) and by assessing the model's diagnostic performance for sarcopenia in a community-based elderly cohort (n = 522).

RESULTS

The 3D U-Net achieved accurate body composition segmentation with an average dice similarity coefficient of 96.5%-98.9% for all masks and 92.3%-99.3% for muscle, abdominal visceral fat, and subcutaneous fat in the validation datasets. The 3D U-Net-derived torso volume of skeletal muscle and fat tissue and the average area of those tissues in the waist were correlated with BIA-derived appendicular lean mass (correlation coefficients: 0.71 and 0.72, each) and fat mass (correlation coefficients: 0.95 and 0.93, each). The 3D U-Net-derived average areas of skeletal muscle and fat tissue in the waist were independently associated with sarcopenia (P < .001, each) with adjustment for age and sex, providing an area under the curve of 0.858 (95% CI, 0.815 to 0.901).

CONCLUSIONS

This deep neural network model enabled the automatic volumetric segmentation of body composition on whole-body CT images, potentially expanding adjunctive sarcopenia assessment on PET-CT scan and volumetric assessment of metabolism in whole-body muscle and fat tissues.

High-Resolution Three-Dimensional Photonic Scan-Derived Equations Improve Body Surface Area Prediction in Diverse Populations

OBJECTIVE

Equations for predicting body surface area (BSA) produce flawed estimates, especially for individuals with obesity. This study aimed to compare BSA measured by a three-dimensional photonic scanner (3DPS) with BSA predicted by six commonly cited prediction equations and to develop new prediction equations if warranted.

METHODS

The 3DPS was validated against manual measurements by breadth caliper for body thicknesses measured at three anatomical sites on a mannequin. BSA was derived from 3DPS whole-body scans of 67 males and 201 females, aged 18 to 83 years, with BMI between 17.8 and 77.8 kg/m2 and varied races/ethnicities.

RESULTS

Width and depth measurements by 3DPS and caliper were within 1%, except for hip, with an error of 1.8%. BSA3DPS differed from BSA predicted by each equation (P < 0.05), except for males by DuBois and DuBois (P = 0.60), Tikuisis (P = 0.27), and Yu (P = 0.45) and for females by Tikuisis (P = 0.70). The combined and sex-specific equations obtained by regressing ln(BSA) on ln(weight in kilograms [W]) and ln(height in meters [H]) are as follows (R2 and SEE correspond to ln[BSA]): combined, BSA3DPS  = 0.03216 × W0.4904  × H0.3769 , R2  = 0.982, SEE = 0.021; males, BSA3DPS  = 0.01624 × W0.4725  × H0.5231 ; and females, BSA3DPS  = 0.01522 × W0.4921  × H0.5231 , R2  = 0.986, SEE = 0.019.

CONCLUSIONS

New height and weight BSA equations improve BSA estimation in individuals with BMI ≥ 40 and in African Americans, Hispanic Americans, and Asian Americans.

Prognostic value of anthropometric measures extracted from whole-body CT using deep learning in patients with non-small-cell lung cancer

INTRODUCTION

The aim of the study was to extract anthropometric measures from CT by deep learning and to evaluate their prognostic value in patients with non-small-cell lung cancer (NSCLC).

METHODS

A convolutional neural network was trained to perform automatic segmentation of subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and muscular body mass (MBM) from low-dose CT images in 189 patients with NSCLC who underwent pretherapy PET/CT. After a fivefold cross-validation in a subset of 35 patients, anthropometric measures extracted by deep learning were normalized to the body surface area (BSA) to control the various patient morphologies. VAT/SAT ratio and clinical parameters were included in a Cox proportional-hazards model for progression-free survival (PFS) and overall survival (OS).

RESULTS

Inference time for a whole volume was about 3 s. Mean Dice similarity coefficients in the validation set were 0.95, 0.93, and 0.91 for SAT, VAT, and MBM, respectively. For PFS prediction, T-stage, N-stage, chemotherapy, radiation therapy, and VAT/SAT ratio were associated with disease progression on univariate analysis. On multivariate analysis, only N-stage (HR = 1.7 [1.2-2.4]; p = 0.006), radiation therapy (HR = 2.4 [1.0-5.4]; p = 0.04), and VAT/SAT ratio (HR = 10.0 [2.7-37.9]; p < 0.001) remained significant prognosticators. For OS, male gender, smoking status, N-stage, a lower SAT/BSA ratio, and a higher VAT/SAT ratio were associated with mortality on univariate analysis. On multivariate analysis, male gender (HR = 2.8 [1.2-6.7]; p = 0.02), N-stage (HR = 2.1 [1.5-2.9]; p < 0.001), and the VAT/SAT ratio (HR = 7.9 [1.7-37.1]; p < 0.001) remained significant prognosticators.

CONCLUSION

The BSA-normalized VAT/SAT ratio is an independent predictor of both PFS and OS in NSCLC patients.

KEY POINTS

• Deep learning will make CT-derived anthropometric measures clinically usable as they are currently too time-consuming to calculate in routine practice. • Whole-body CT-derived anthropometrics in non-small-cell lung cancer are associated with progression-free survival and overall survival. • A priori medical knowledge can be implemented in the neural network loss function calculation.

Computer tomography-based body surface area evaluation for drug dosage: Quantitative radiology versus anthropomorphic evaluation

OBJECTIVE

The measure of body surface area (BSA) is a standard for planning optimal dosing in oncology. This index is derived from a model having questionable performances. In this study, we proposed measurement of BSA from whole body CT images (iBSA). We tested the reliability of iBSA assessments and simulated the impact of our approach on patient chemotherapy dosage planning.

METHODS

We first evaluated accuracy and precision of iBSA in measuring 14 phantom and 11 CT test-retest images.Secondly, we retrospectively analyzed 26 whole body PET-CT scans to evaluate inter-method variability between iBSA and the most used anthropomorphic models, notably the "Du Bois and Du Bois" model. Finally, we simulated the impact on chemotherapy dose planning of capecitabine based on iBSA.

RESULTS

Precision and accuracy of iBSA measurement featured a standard deviation of 1.11% and a mean error of 1.53%. Inter-method variability between iBSA and "Du Bois and Du Bois" assessment featured a standard deviation of 4.11% leading to a reclassification rate of capecitabine of 32.5%.

CONCLUSIONS

iBSA could help the oncologist in standardizing assessments for chemotherapy planning. iBSA could also be relevant for applications such as comprehensive body composition and provide a sensitive measurement for changes related to nutritional intake or other metabolism.

Body map of regional vs. whole body sweating rate and sweat electrolyte concentrations in men and women during moderate exercise-heat stress

This study determined the relations between regional (REG) and whole body (WB) sweating rate (RSR and WBSR, respectively) as well as REG and WB sweat Na⁺ concentration ([Na⁺]) during exercise. Twenty-six recreational athletes (17 men, 9 women) cycled for 90 min while WB sweat [Na⁺] was measured using the washdown technique. RSR and REG sweat [Na⁺] were measured from nine regions using absorbent patches. RSR and REG sweat [Na⁺] from all regions were significantly ( P < 0.05) correlated with WBSR ( r = 0.58-0.83) and WB sweat [Na⁺] ( r = 0.74-0.88), respectively. However, the slope and y-intercept of the regression lines for most models were significantly different than 1 and 0, respectively. The coefficients of determination ( r²) were 0.44-0.69 for RSR predicting WBSR [best predictors: dorsal forearm ( r² = 0.62) and triceps ( r² = 0.69)] and 0.55-0.77 for REG predicting WB sweat [Na⁺] [best predictors: ventral forearm ( r² = 0.73) and thigh ( r² = 0.77)]. There was a significant ( P < 0.05) effect of day-to-day variability on the regression model predicting WBSR from RSR at most regions but no effect on predictions of WB sweat [Na⁺] from REG. Results suggest that REG cannot be used as a direct surrogate for WB sweating responses. Nonetheless, the use of regression equations to predict WB sweat [Na⁺] from REG can provide an estimation of WB sweat [Na⁺] with an acceptable level of accuracy, especially using the forearm or thigh. However, the best practice for measuring WBSR remains conventional WB mass balance calculations since prediction of WBSR from RSR using absorbent patches does not meet the accuracy or reliability required to inform fluid intake recommendations. NEW & NOTEWORTHY This study developed a body map of regional sweating rate and regional (REG) sweat electrolyte concentrations and determined the effect of within-subject (bilateral and day-to-day) and between-subject (sex) factors on the relations between REG and the whole body (WB). Regression equations can be used to predict WB sweat Na⁺ concentration from REG, especially using the forearm or thigh. However, prediction of WB sweating rate from REG sweating rate using absorbent patches does not reach the accuracy or reliability required to inform fluid intake recommendations.

Three-dimensional imaging is a novel and reliable technique to measure total body surface area

OBJECTIVE

The aim of this study was to explore the diverse clinimetric aspects of three-dimensional imaging measurements of TBSA in clinical practice compared with the methods currently used in clinical practice (i.e., the rule of nines and palm method) to measure TBSA in clinical practice.

METHOD

To assess reliability, two independent researchers measured the TBSAs of 48 burn patients using Artec MHT™ Scanner and software. Subsequently, a resident and burn specialist estimated the TBSA of the same wounds using the rule of nines and palm method.

RESULTS

Three-dimensional imaging showed excellent inter-observer reliability, with an intra-class correlation coefficient (ICC) of 0.99, standard error of measurement (SEM) of 0.054, and limits of agreement (LoA) of ±0.15×the mean TBSA (between the measurements of two researchers). The inter-observer reliability of the methods used in current clinical practice was less reliable, with an ICC of 0.91, SEM of 0.300 and LoA of ±0.78×the mean TBSA. The inter-observer reliability was least reliable between three-dimensional imaging and the residents compared with the burn specialists for the estimated TBSA, with an ICC of 0.68, SEM of 0.69 and LoA of ±1.49×the mean TBSA.

CONCLUSION

The inter-observer reliability of three-dimensional imaging was superior compared with the rule of nines and palm method.

Body mass estimation from the skeleton: An evaluation of 11 methods

Estimating an individual body mass (BM) from the skeleton is a challenge for forensic anthropology. However, identifying someone's BMI (Body Mass Index) category, i.e. underweight, normal, overweight or obese, could contribute to identification. Individual BM is also known to influence the age-at-death estimation from the skeleton. Several methods are regularly used by both archaeologists and forensic practitioners to estimate individual BM. The most commonly used methods are based on femoral head breadth, or stature and bi-iliac breadth. However, those methods have been created from mean population BMs and are therefore meant to estimate the average BM of a population. Being that they are based on individual BM data and estimated femoral cortical areas, the newest published methods are supposed to be more accurate. We evaluated the accuracy and reliability of the most commonly used and most recent BM estimation methods (n=11) on a sample of 64 individuals. Both sexes and all BMI categories are represented, as well as a wide range of BM. Ages in this sample range from 20 to 87 years of age. Absolute and real differences between actual BM and estimated BM were assessed; they determined the accuracy for individual BM estimation and for average BM estimation of a population, respectively. The proportion of the sample whose estimated BM falls within ±10% and ±20% of their actual BM determines the reliability of the methods in our sample for, respectively, individual BM estimation and average BM of a population. The tested methods result in an absolute difference of 11kg-26kg±10kg with regards to prediction of individuals actual BM. The real differences are very variable from method to method, ranging from -14kg to 25kg. None of the tested methods is able to estimate BM of half of the sample within ±10% of their actual BM but most of them can estimate BM of more than half of the sample within ±20% of their actual BM. The errors increase with increasing BM, demonstrating a bias in all the methods. No bone variable tested correlated with BM. BMI categories were correctly predicted for less than 50% of the sample in most cases. In conclusion, our study demonstrates that the 11 methods tested are not suited for estimating individual BM or for predicting BMI categories. However, they are accurate and reliable enough for estimating the average BM of a population.

Body composition estimation from selected slices: equations computed from a new semi-automatic thresholding method developed on whole-body CT scans

Background

Estimating volumes and masses of total body components is important for the study and treatment monitoring of nutrition and nutrition-related disorders, cancer, joint replacement, energy-expenditure and exercise physiology. While several equations have been offered for estimating total body components from MRI slices, no reliable and tested method exists for CT scans. For the first time, body composition data was derived from 41 high-resolution whole-body CT scans. From these data, we defined equations for estimating volumes and masses of total body AT and LT from corresponding tissue areas measured in selected CT scan slices.

Methods

We present a new semi-automatic approach to defining the density cutoff between adipose tissue (AT) and lean tissue (LT) in such material. An intra-class correlation coefficient (ICC) was used to validate the method. The equations for estimating the whole-body composition volume and mass from areas measured in selected slices were modeled with ordinary least squares (OLS) linear regressions and support vector machine regression (SVMR).

Results and Discussion

The best predictive equation for total body AT volume was based on the AT area of a single slice located between the 4th and 5th lumbar vertebrae (L4-L5) and produced lower prediction errors (|PE| = 1.86 liters, %PE = 8.77) than previous equations also based on CT scans. The LT area of the mid-thigh provided the lowest prediction errors (|PE| = 2.52 liters, %PE = 7.08) for estimating whole-body LT volume. We also present equations to predict total body AT and LT masses from a slice located at L4-L5 that resulted in reduced error compared with the previously published equations based on CT scans. The multislice SVMR predictor gave the theoretical upper limit for prediction precision of volumes and cross-validated the results.

Higher incidence of hypotension episodes in women during the sub-acute phase of ST elevation myocardial infarction and relationship to covariates

OBJECTIVE

The introduction of primary percutaneous coronary intervention (PPCI) has modified the profile of ST elevation myocardial infarction (STEMI) patients. Occurrence and prognostic significance of hypotension episodes are not known in PPCI treated STEMI patients. It is also not known whether and/or how the hypotension episodes correlate with the degree of myocardial damage and whether there are any sex differences.

METHODS

Data of 293 consecutive STEMI patients (189 males) treated by PPCI and without cardiogenic shock were analyzed. Blood pressure was measured noninvasively. A hypotensive episode was defined as a systolic blood pressure below 90 mmHg over a period of at least 30 minutes.

RESULTS

A hypotensive episode was observed in 92 patients (31.4%). Female sex was the strongest independent predictor of hypotension episodes (p < 0.0001), while there was no relationship to electrocardiographic STEMI localization. Hypotensive patients had significantly higher levels of troponin T and brain natriuretic peptide; hypotensive episodes were particularly frequent in women with increased troponin T. Treatment with angiotensin-converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB) and betablockers was less frequent in hypotensive patients. After a mean 20-month follow-up, all-cause mortality did not differ between hypotensive patients and others. However, mortality in hypotensive patients who did not tolerate ACEI/ARB therapy was significantly higher compared to other hypotensive patients (p = 0.016).

CONCLUSION

Hypotension episodes are not uncommon in the sub-acute phase of contemporarily treated STEMI patients with a striking difference between sexes-female sex was the strongest independent predictor of hypotension episodes. Hypotensive episodes may lead to a delay in pharmacotherapy which influences prognosis. Higher incidence of hypotension in women could at least partially explain the sex-related differences in the use of cardiovascular pharmacotherapy which was repeatedly observed in various studies.