Distensibility Measurements Research Articles

Intraoperative Assessment of Esophagogastric Junction Distensibility During Laparoscopic Heller Myotomy.

We sought to characterize the changes in esophagogastric junction (EGJ) distensibility during Heller Myotomy with Dor fundoplication using the EndoFLIP device. Intraoperative distensibility measurements on 14 patients undergoing Heller myotomy with Dor fundoplication were conducted over an 18-month period. Minimum esophageal diameter, cross-sectional areas, and distensibility index were measured at 30 and 40 mL catheter volumes before myotomy, postmyotomy, and following Dor fundoplication. Distensibility index is defined as the narrowest cross-sectional area divided by the corresponding pressure expressed in mm/mm Hg. Heller myotomy was found to lead to significant changes in the distensibility characteristics of the EGJ. Minimum esophageal diameter and EGJ distensibility increased significantly with Heller myotomy.

Esophagogastric junction distensibility measurements during hydraulic dilation therapy in achalasia patients

SUMMARYIncreasing evidence suggests that esophagogastric junction (EGJ) distensibility is predictive of long-term clinical success after achalasia treatment. A new commercially available hydraulic dilation balloon is capable of measuring EGJ opening diameters whilst simultaneously dilating the EGJ. Deployed alongside the endoscope under direct visualization, it is used for dilation of the lower esophageal sphincter in patients with achalasia. Impedance measurement electrodes are incorporated in the catheter shaft in the dilation balloon, which allows measuring the diameter of the EGJ and displaying it in real time before, during and after dilation. This obviates the need for fluoroscopy during the dilation procedure. The extent of recoil of the EGJ after dilation potentially provides a measurement that could be incorporated into a clinical rule for predicting therapeutic success after dilation.

Intima-media thickness and arterial function in obese and non-obese children

BackgroundObesity is an independent cardiovascular risk factor that contributes to the development of atherosclerosis. Subclinical forms of the disease can be assessed via sonographic measurement of carotid intima-media thickness (cIMT) and distensibility – both may already be altered in childhood. As childhood obesity increases to an alarming extent, this study compares vascular data of obese with normal weight boys and girls to investigate the influence of obesity on cIMT and distensibility of the carotid arteries.MethodscIMT and distensibility of 46 obese children (27 girls) aged 7–17 years were compared with measures of 46 sex- and age-matched normal weight controls. cIMT and distensibility were measured by B- and M-mode ultrasound and expressed as standard deviation scores (SDS). Arterial distensibility was defined by arterial compliance (AC), elastic modulus (Ep), stiffness index β (β), and local pulse wave velocity β (PWV β).ResultsObese girls had significantly stiffer arteries compared with normal weight girls (Ep SDS 0.64 ± 1.24 vs. 0 ± 1.06, β SDS 0.6 ± 1.17 vs. -0.01 ± 1.06 p < .01, PWV β 0.54 ± 1.2 vs. -0.12 ± 1.05 p < .05). No significant differences were observed for boys. In multiregression analysis, BMI significantly influenced Ep, β and PWV β but not cIMT and AC.ConclusionsObese girls seemed to be at higher cardiovascular risk than boys, expressed by stiffer arteries in obese girls compared with normal weight girls. Overall, BMI negatively influenced parameters of arterial stiffness (Ep, β and PWV β) but not compliance or cIMT.

Pulmonary arterial compliance: How and why should we measure it?

The pulmonary circulation is a high-flow/low-pressure system, coupled with a flow generator chamber–the right ventricle–, which is relatively unable to tolerate increases in afterload. A right heart catheterization, using a fluid-filled, balloon-tipped Swan-Ganz catheter allows the measurement of all hemodynamic parameters characterizing the pulmonary circulation: the inflow pressure, an acceptable estimate the outflow pressure, and the pulmonary blood flow. However, the study of the pulmonary circulation as a continuous flow system is an oversimplification and a thorough evaluation of the pulmonary circulation requires a correct understanding of the load that the pulmonary vascular bed imposes on the right ventricle, which includes static and dynamic components. This is critical to assess the prognosis of patients with pulmonary hypertension or with heart failure.Pulmonary compliance is a measure of arterial distensibility and, either alone or in combination with pulmonary vascular resistance, gives clinicians the possibility of a good prognostic stratification of patients with heart failure or with pulmonary hypertension. The measurement of pulmonary arterial compliance should be included in the routine clinical evaluation of such patients.

Increased intima-media thickness is not associated with stiffer arteries in children.

Subclinical atherosclerosis can be assessed via sonographic measurement of intima-media thickness and carotid artery distensibility, both may already be pathologically altered in childhood. Therefore, the purpose of this study was to provide reference percentiles and investigate possible associations between alterations of intima-media thickness and distensibility. Carotid intima-media thickness and distensibility was measured via B- and M-mode ultrasound. Distensibility was defined by arterial compliance, elastic modulus, stiffness parameter β, and local pulse wave velocity β. Age- and height-dependent reference values were calculated separately for boys and girls among 690 (intima-media thickness) and 870 (distensibility) non-obese children aged 7-17 years. Intima-media thickness and distensibility did not increase significantly with age or differ between boys and girls. Systolic blood pressure and body mass index were independent predictors of intima-media thickness, while an increased systolic blood pressure or pulse pressure was associated with stiffer arteries. Increased intima-media thickness was accompanied by higher arterial compliance and lower stiffness. Using this healthy cohort, we describe a functional and non-pathological arterial adaptation wherein an increase in intima-media thickness is not associated with stiffer arteries.

The role of computed tomography in the diagnosis of acute and chronic pulmonary embolism.

Pulmonary embolism (PE) is a potentially life threatening condition requiring adequate diagnosis and treatment. Computed tomography pulmonary angiography (CTPA) is excellent for including and excluding PE, therefore CT is the first-choice diagnostic imaging technique in patients suspected of having acute PE. Due to its wide availability and low invasiveness, CTPA tends to be overused. Correct implementation of clinical decision rules in diagnostic workup for PE improves adequate use of CT. Also, CT adds prognostic value by evaluating right ventricular (RV) function. CT-assessed RV dysfunction and to lesser extent central emboli location predicts PE-related mortality in normotensive and hypotensive patients, while PE embolic obstruction index has limited prognostic value. Simple RV/left ventricular (LV) diameter ratio measures >1.0 already predict risk for adverse outcome, whereas ratios <1.0 can safely exclude adverse outcome. Consequently, assessing the RV/LV diameter ratio may help identify patients who are potential candidates for treatment at home instead of treatment in the hospital. A minority of patients develop chronic thromboembolic pulmonary hypertension (CTEPH) following acute PE, which is a life-threatening condition that can be diagnosed by CT. In proximal CTEPH, involving the more central pulmonary arteries, thrombectomy usually results in good outcome in terms of both functional status and long-term survival rate. CT is becoming the imaging method of choice for diagnosing CTEPH as it can identify patients who may benefit from thrombectomy. New CT developments such as distensibility measurements and dual-energy or subtraction techniques may further refine diagnosis and prognosis for improved patient care.

Measurement of Esophagogastric Junction Distensibility May Assist in Selecting Patients for Endoluminal Gastroesophageal Reflux Disease Surgery.

TO THE EDITOR: I read with interest the study by Smeets et al,1 who evaluated the association between pre-operative distensibility measurements and objective and clinical outcomes after transoral incisionless fundoplication (TIF) surgery. The study concluded that distensibility measurements have no added value in the pre-operative diagnostic work-up or in the post-procedure evaluation of endoluminal anti-reflux therapy. This study adds to a growing body of literature,2–9 which in general suggests that there is little benefit in the use of any of the standard gastrodiagnostic methods to predict post-surgical outcomes in gastroesophageal reflux disease (GERD) surgery. The outcomes of such functional surgery are operator and technique dependent, producing highly variable gastroesophageal junction (GEJ) constructs.10 It is therefore questionable whether the geometry of the GEJ pre-surgery alone could be reasonably expected to predict how the GEJ will perform post-surgically. However the authors, in my view, have made an important contribution in addressing a question of significant clinical importance, namely as to whether a pre-operative measurement can help stratify patients who might reasonably benefit from a lower risk transoral GERD procedure versus, for example, a laparoscopic fundoplication. Using criteria of a distensibility cut-off value of 2.3 mm2/mmHg (measured at 30 mL distension volume) combined with acid exposure time < 11%, they noted that 94% of the patients meeting these combined pre-operative criteria had normalized acid exposure time at 6 months after TIF surgery. On a technical note, I would question whether distensibility is a measurement best suited for the evaluation of TIF procedure itself. Distensibility is calculated by dividing the minimum cross sectional area of the GEJ by balloon distending pressure. Observational experience of the TIF procedure would suggest that the mode of action of the EsophyX device serves to lengthen the high pressure zone as distinct from tightening it. This mode of action is somewhat different from the clear barrier to distension of the GEJ created during cruroplasty, or with an external wrap. I would alternatively hypothesize that the immediate post-operative tightening presented in Table 4 may be due to intra-procedural edema which has resolved by the time the 6-month measurement was taken. In conclusion, I would disagree that distensibility measurements have no added value in the pre-operative diagnostic work-up, but believe that they may offer an important adjunctive measurement to assist a surgeon decide whether a more minimally invasive approach to GERD surgery should be offered to a patient.

Functional lumen imaging of the gastrointestinal tract

This nonsystematic review aims to describe recent developments in the use of functional lumen imaging in the gastrointestinal tract stimulated by the introduction of the functional lumen imaging probe. When ingested food in liquid and solid form is transported along the gastrointestinal tract, sphincters provide an important role in the flow and control of these contents. Inadequate function of sphincters is the basis of many gastrointestinal diseases. Despite this, traditional methods of sphincter diagnosis and measurement such as fluoroscopy, manometry, and the barostat are limited in what they can tell us. It has long been thought that measurement of sphincter function through resistance to distension is a better approach, now more commonly known as distensibility testing. The functional lumen imaging probe is the first medical measurement device that purports in a practical way to provide geometric profiling and measurement of distensibility in sphincters. With use of impedance planimetry, an axial series of cross-sectional areas and pressure in a catheter-mounted allantoid bag are used for the calculation of distensibility parameters. The technique has been trialed in many valvular areas of the gastrointestinal tract, including the upper esophageal sphincter, the esophagogastric junction, and the anorectal region. It has shown potential in the biomechanical assessment of sphincter function and characterization of swallowing disorders, gastroesophageal reflux disease, eosinophilic esophagitis, achalasia, and fecal incontinence. From this early work, the functional lumen imaging technique has the potential to contribute to a better and more physiological understanding of narrowing regions in the gastrointestinal tract in general and sphincters in particular.

Aortic Pulse Wave Velocity in Healthy Children and Adolescents: Reference Values for the Vicorder Device and Modifying Factors.

Aortic pulse wave velocity (PWV), an indicator of arterial stiffness, independently predicts cardiovascular mortality risk in adults. Arterial stiffening advances with age and seems accelerated in children with certain disease conditions such as chronic kidney disease or diabetes. The Vicorder, an oscillometric device to measure PWV, has been validated in children, but reference values in a large pediatric cohort, association to carotid stiffness and influence of individual and family risk factors have not been determined. Pulse waves were captured in 1,003 healthy children (aged 6-18 years) in 6 centers and gender-specific reference data normalized to age/height were constructed. In 589 children carotid distensibility and intima media thickness were measured. Gestational and family history was reported. PWV correlated with age (r = 0.57, P < 0.0001) with significant gender-related differences starting at age 9. Further significant correlations were seen for height, weight, body mass index, blood pressure, pulse pressure, and heart rate. Independent predictors for PWV in a multivariate regression analysis were gender, age, height, weight, mean arterial pressure, and heart rate. Risk factors for higher PWV included small for gestational age at birth, secondhand smoking, parental hypertension, and obesity. PWV showed weak correlations with 2 of the carotid distensibility measures, but not with intima media thickness. This study defines reference values for PWV captured by the Vicorder device in children and adolescents and reveals associations with potential cardiovascular risk factors in a healthy population. Gender-specific percentiles for age/height will allow for the assessment of pediatric cohorts using this oscillometric method.

Impaired aortic elastic properties in primary osteoarthritis.

Osteoarthritis is one of the most common chronic diseases and associated with increased cardiovascular comorbidity and deaths. Elastic properties of aorta are closely associated with cardiovascular mortality and morbidity. In our study, we aimed to evaluate aortic stiffness in primary osteoarthritis patients. A total of 160 patients including 80 patients with primary knee osteoarthritis and 80 controls without osteoarthritis were included in the study. Additionally, osteoarthritis patients were divided into four subgroups according to the severity of the disease. Aortic parameters were evaluated by using transthoracic echocardiography method. While measurements of aortic stiffness of osteoarthritis group were higher compared to the control group (p < 0.01), aortic strain and aortic distensibility measurements of osteoarthritis group are lower than the control group (p < 0.01). Additionally, it was determined that as the severity of osteoarthritis increased also aortic stiffness increased highly significantly (p = 0.001). Presence and severity of osteoarthritis are closely associated with elastic properties of aorta, which are correlated with cardiovascular mortality and morbidity.

Does Measurement of Esophagogastric Junction Distensibility by EndoFLIP Predict Therapy- responsiveness to Endoluminal Fundoplication in Patients With Gastroesophageal Reflux Disease?

Background/AimsIn patients with gastroesophageal reflux disease (GERD), an increased esophagogastric junction (EGJ) distensibility has been described. Assessment of EGJ distensibility with the endoscopic functional luminal imaging probe (EndoFLIP) technique might identify patients responsive to transoral incisionless fundoplication (TIF), whereas postoperative measurement of EGJ distensibility might provide insight into the antireflux mechanism of TIF. Therefore, we investigated the value of the EndoFLIP technique in GERD patients treated by TIF.MethodsForty-two GERD patients underwent EGJ distensibility measurement before TIF using the EndoFLIP technique. In a subgroup of 25 patients, EndoFLIP measurement was repeated both postoperative and at 6 months follow-up. Treatment outcome was assessed according to esophageal acid exposure time (AET; objective outcome) and symptom scores (clinical outcome) 6 months after TIF.ResultsMultiple logistic regression analysis showed that preoperative EGJ distensibility (OR, 0.16; 95% CI, 0.03–0.78; P = 0.023) and preoperative AET (OR, 0.62; 95% CI, 0.42–0.90; P = 0.013) were independent predictors for objective treatment outcome but not for clinical outcome after TIF. The best cut-off value for objective outcome was 2.3 mm2/mmHg for preoperative EGJ distensibility and 11% for preoperative AET. EGJ distensibility decreased direct postoperative from 2.0 (1.2–3.3) to 1.4 (1.0–2.2) mm2/mmHg (P = 0.014), but increased to 2.2 (1.5–3.0) at 6 months follow-up (P = 0.925, compared to preoperative).ConclusionsPreoperative EGJ distensibility and preoperative AET were independent predictors for objective treatment outcome but not for clinical outcome after TIF. According to our data, the EndoFLIP technique has no added value either in the preoperative diagnostic work-up or in the post-procedure evaluation of endoluminal antireflux therapy.

Arterial stiffness and progression of structural brain changes: The SMART-MR study.

To examine the cross-sectional and prospective associations between arterial stiffness and structural brain changes within the Second Manifestations of Arterial Disease-Magnetic Resonance (SMART-MR) study, a prospective cohort study among patients with manifest arterial disease. Distension measurements of the common carotid arteries and a brain MRI were performed in 526 patients (mean age 59 ± 10 years). After a mean follow-up of 4.1 years (range 3.6-5.8), brain MRI was repeated in 308 patients. Brain segmentation was used to quantify total brain volume, cortical gray matter volume, ventricular volume, and white matter lesion (WML) volume (relative to intracranial volume). Infarcts were rated visually. Cross-sectional multivariable regression analyses showed that 1 SD decrease in carotid distension, indicating increased arterial stiffness, was associated with smaller relative total brain and cortical gray matter volumes (B = -0.24%, 95% confidence interval [CI] -0.44 to -0.04%, and B = -0.47%, 95% CI -0.75 to -0.19%), with larger WML volume (B = 0.09%, 95% CI -0.01 to 0.19%), and with higher risk of having nonlacunar (cortical or large subcortical) brain infarcts (relative risk = 1.44, 95% CI 1.14 to 1.81). However, our prospective findings showed that carotid distension was not significantly associated with progression of brain atrophy, WML volume, or brain infarcts. In this population of patients with manifest arterial disease, stiffening of the carotid arteries was cross-sectionally associated with more brain atrophy, WML volume, and nonlacunar infarcts, but did not lead to changes in brain volumes or infarcts after 4 years.

The influence of intraluminal thrombus on noninvasive abdominal aortic aneurysm wall distensibility measurement.

Abdominal aortic aneurysm wall distensibility can be estimated by measuring pulse pressure and the corresponding sac volume change, which can be obtained by measuring wall displacement. This approach, however, may introduce error if the role of thrombus in assisting the wall in bearing the pulse pressure loading is neglected. Our aim was to introduce a methodology for evaluating and potentially correcting this error in estimating distensibility. Electrocardiogram-gated computed tomography images of eleven patients were obtained, and the volume change between diastole and systole was measured. Using finite element procedures, we determined the equivalent pulse pressure loading that should be applied to the wall of a model where thrombus was digitally removed, to yield the same sac volumetric increase caused by applying the luminal pulse pressure to the model with thrombus. The equivalent instead of the measured pulse pressure was used in the distensibility expression. For a relative volumetric thrombus deposition (V ILT) of 50%, a 62% distensibility underestimation resulted when thrombus role was neglected. A strong linear correlation was observed between distensibility underestimation and V ILT. To assess the potential value of noninvasive wall distensibility measurement in rupture risk stratification, the role of thrombus on wall loading should be further investigated.

Electrocardiogram-gated 320-slice multidetector computed tomography for the measurement of pulmonary arterial distensibility in chronic thromboembolic pulmonary hypertension.

BackgroundWe aimed to study whether pulmonary arterial distensibility (PAD) correlates with hemodynamic parameters in chronic thromboembolic pulmonary hypertension (CTEPH) using electrocardiogram (ECG)-gated 320-slice multidetector computed tomography (MDCT).Methods and FindingsECG-gated 320-slice MDCT and right heart catheterization (RHC) was performed in 53 subjects (60.6±11.4 years old; 37 females) with CTEPH. We retrospectively measured the minimum and maximum values of the cross sectional area (CSA) of the main pulmonary artery (mainPA), right pulmonary artery (rtPA), and left pulmonary artery (ltPA) during one heartbeat. PAD was calculated using the following formula: PAD = [(CSAmaximum−CSAminimum)/CSAmaximum]×100(%). The correlation between hemodynamic parameters and PAD was assessed. Mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR) were 40.8±8.7 mmHg and 8.3±3.0 wood units, respectively. PAD values were as follows: mainPA (14.0±5.0%), rtPA (12.8±5.6%), and ltPA (9.7±4.6%). Good correlations existed between mainPAD, with mPAP (r = −0.594, p<0.001) and PVR (r = −0.659, p<0.001). The correlation coefficients between rtPAD and ltPAD with pulmonary hemodynamics were all lower or equal than for mainPAD.ConclusionsPAD measured using ECG-gated 320-slice MDCT correlates with pulmonary hemodynamics in subjects with CTEPH. The mainPA is suitable for PAD measurement.

Carotid haemodynamics during sympathetic nervous system stimulation via handgrip and cold pressor testing in young healthy subjects: A feasibility study

IntroductionAssessing arterial and haemodynamic properties in response to a physiological perturbation might provide additional information on an individual's “vascular health”. The aim of this study was to assess the feasibility of measuring changes in carotid stiffness and haemodynamics in response to sympathetic nervous system stressors, such as the Hand Grip Test (HGT) and the Cold Pressor Test (CPT). MethodsA non-invasive protocol, consisting of two HGT's at 30% and 40% of maximal voluntary contraction and a CPT, was performed in 12 young healthy volunteers (6 males/6 females). Measurements included continuous finger blood pressure recordings (NexFin; non-dominant hand) and ultrasound measurement of common carotid diameter distension and flow velocity at discrete moments in time during the protocol (GE Vivid 7 system). Carotid distension (ΔD/D), local wave speed using the waterhammer equation (PWVWH) and reflection magnitude (RM; ratio of backward to forward diameter wave) were derived from the data. ResultsConsistent with the overall increase in blood pressure, carotid diameter increased while ΔD/D decreased. PWVWH and RM showed high variability during both HGT's and CPT. ConclusionIt is feasible to monitor the carotid haemodynamic response to selected sympathetic nervous system stimulus. Moreover, the analysis showed supporting evidence of specific physiological response to regulate adequately each stress stimulus.

Esophagogastric junction distensibility measurements during Heller myotomy and POEM for achalasia predict postoperative symptomatic outcomes.

The functional lumen imaging probe (FLIP) is a novel diagnostic tool that can be used to measure esophagogastric junction (EGJ) distensibility. In this study, we performed intraoperative FLIP measurements during laparoscopic Heller myotomy (LHM) and peroral esophageal myotomy (POEM) for treatment of achalasia and evaluated the relationship between EGJ distensibility and postoperative symptoms. Distensibility index (DI) (defined as the minimum cross-sectional area at the EGJ divided by distensive pressure) was measured with FLIP at two time points during LHM and POEM: (1) at baseline after induction of anesthesia, and (2) after operation completion. Measurements were performed in 20 patients undergoing LHM and 36 undergoing POEM. Both operations resulted in an increase in DI, although this increase was larger with POEM (7 ± 3.1 vs. 5.1 ± 3.4 mm(2)/mmHg, p < .05). The two patients (both LHM) with the smallest increases in DI (1 and 1.6 mm(2)/mmHg) both had persistent symptoms postoperatively and, overall, LHM patients with larger increases in DI had lower postoperative Eckardt scores. In the POEM group, there was no correlation between change in DI and symptoms; however, all POEM patients experienced an increase in DI of >3 mm(2)/mmHg. When all patients were divided into thirds based on final DI, none in the lowest DI group (<6 mm(2)/mmHg) had symptoms suggestive of reflux (i.e., GerdQ score >7), as compared with 20 % in the middle third (6-9 mm(2)/mmHg) and 36 % in the highest third (>9 mm(2)/mmHg). Patients within an "ideal" final DI range (4.5-8.5 mm(2)/mmHg) had optimal symptomatic outcomes (i.e., Eckardt ≤ 1 and GerdQ ≤ 7) in 88 % of cases, compared with 47 % in those with a final DI above or below that range (p < .05). Intraoperative EGJ distensibility measurements with FLIP were predictive of postoperative symptomatic outcomes. These results provide initial evidence that FLIP has the potential to act as a useful calibration tool during operations for achalasia.

Relation of Systolic, Diastolic, and Pulse Pressures and Aortic Distensibility With Atrial Fibrillation (from the Multi-Ethnic Study of Atherosclerosis)

Previous research suggests that elevated pulse pressure (PP) is a risk factor for atrial fibrillation (AF) independently of mean arterial pressure (MAP). PP may serve as an indirect measure of aortic stiffness (reduced distensibility), but whether directly measured aortic distensibility is related to risk for AF has not yet been studied. This analysis included 6,630 participants aged 45 to 84years from the Multi-Ethnic Study of Atherosclerosis. At baseline, blood pressure and other relevant covariates were measured using standardized protocols. Magnetic resonance imaging-based aortic distensibility was measured in 3,441 participants. Incident AF was identified from hospitalization discharge codes and Medicare claims. Multivariate Cox models were used to estimate the association of blood pressure components and aortic distensibility with AF risk. During a mean follow-up of 7.8years, 307 AF events (137 among those with aortic distensibility measurements) were identified. In multivariate-adjusted models simultaneously including MAP and PP, each 1-SD increase in PP was associated with a 29% increased risk of AF (95% confidence interval 5% to 59%, p= 0.02), with MAP not being associated with increased AF risk. Overall, aortic distensibility was not consistently associated with AF risk: after removing outliers, each 1-SD increase in aortic distensibility was associated with a 9% increased risk of AF (95% confidence interval-22% to 51%, p= 0.63). In conclusion, in this large community-based cohort, we found that PP, but not MAP or aortic distensibility, was a significant risk factor for AF, emphasizing the importance of PP when assessing the risk for developing AF. Our results cast doubt on the clinical utility of aortic distensibility as a predictor for the development of AF.

105 Cardiac Mri Assessment Of Pulse Wave Velocity And Aortic Distensibility Following Treatment Of Aortic Stenosis

BackgroundArterial stiffness is an independent predictor of cardiovascular mortality and can be characterised by CMR measurement of aortic distensibility (AD) and pulse wave velocity (PWV).AimTo compare AD and PWV in...

855 Measurement of Esophagogastric Junction Distensibility Identifies a Subgroup of Achalasia Patients With Manometrically Normal LES Relaxation

to have impedance recording sites spaced 2 cm apart and positioned through the EGJ and UES. The two techniques used to measure the IBH utilize the nadir impedance to highlight the liquid to mucosa/air interface using the impedance color topography contour plot and the spatial impedance variation plot. The impedance topography method utilizes a smart mouse tool to measure the distance from the proximal aspect of the EGJ to the top of the topographic color change during end-expiration. The spatial impedance variation plot presents the instantaneous impedance change along the axial length of the esophagus. Interpolation is utilized to smooth out the curve and the range for the impedance measure is set at the nadir impedance to delineate the inflection point where the liquid interface occurs. The IBH is measured as the location along the catheter where the nadir impedance inflection occurs to signify the top of the bolus.

Daily assessment of arterial distensibility in a pediatric population before and after smoking cessation

OBJECTIVES:Cigarette smoking is an important modifiable cardiovascular risk factor associated with increased stiffness of the large arteries in adulthood. This study aimed to 1) evaluate arterial distensibility and echocardiographic measures in adolescent smokers before and after participation in a successful smoking cessation program and to 2) compare the findings obtained with data from a control population of healthy non-smokers.METHODS:A total of 31 young smoking subjects (58.1% male; range: 11-18 years old; mean: 16.5±1.4 years old; mean tobacco consumption: 2.6±0.6 years) were examined before commencing and after taking part for at least 1 year in a smoking cessation program (mean: 1.4±0.3 years). Arterial stiffness was measured using the previously validated QKd100-60 method. Twenty-four-hour ambulatory blood pressure monitoring and transthoracic echocardiography were also performed.RESULTS:(Smokers before abuse cessation vs. smokers after abuse cessation) systolic blood pressure: p<0.004; diastolic blood pressure: p<0.02; mean blood pressure: p<0.01; QKd100-60 value: 183±5 vs. 196±3 msec, p<0.009; p = ns for all echocardiographic parameters. (Smokers after abuse cessation vs. controls) systolic blood pressure: p<0.01; diastolic blood pressure: p<0.03; mean blood pressure: p<0.02; QKd100-60 value: 196±3 vs. 203±2 msec, p<0.04; p<0.02, p<0.01, and p<0.05 for the interventricular septum, posterior wall, and left ventricular mass, respectively.CONCLUSIONS:Despite successful participation in a smoking cessation program, arterial distensibility improved but did not normalize. This finding underlines the presence of the harmful effect of arterial rigidity in these individuals, despite their having quit smoking and their young ages, thus resulting in the subsequent need for a lengthy follow-up period.