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PubMed1980

Studies of female urethral pressure profile. Part I. The normal urethral pressure profile.

The urethral pressure profile is influenced by the degree of patient relaxation, which explains marked variations in measured pressure values among normal subjects, as well as the frequent lack of reproducibility in a given subject. The quality of relaxation can be estimated by observing the difference between maximum resting and maximum holding pressures. The most reproducible parameters are 1) the total urethral length, 2) the length to the point of maximum pressure and 3) the ratio of area to the point of maximum pressure over total area. Changes in intravesical volume do not produce significant differences in peak pressure, total area or area to maximum pressure. When subjects were asked to strain the pressure in the proximal urethra increased by 60% of the intravesical pressure observed, even in the absence of a vesical neck opening.

Adult↗

PubMedDate not supplied

Role of blood pressure and other variables in the differential cardiovascular event rates noted in the Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm (ASCOT-BPLA).

BACKGROUND: Results of the Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm (ASCOT-BPLA) show significantly lower rates of coronary and stroke events in individuals allocated an amlodipine-based combination drug regimen than in those allocated an atenolol-based combination drug regimen (HR 0.86 and 0.77, respectively). Our aim was to assess to what extent these differences were due to significant differences in blood pressures and in other variables noted after randomisation. METHODS: We used data from ASCOT-BPLA (n=19 257) and compared differences in accumulated mean blood pressure levels at sequential times in the trial with sequential differences in coronary and stroke events. Serial mean matching for differences in systolic blood pressure was used to adjust HRs for differences in these events. We used an updated Cox-regression model to assess the effects of differences in accumulated mean levels of various measures of blood pressure, serum HDL-cholesterol, triglycerides and potassium, fasting blood glucose, heart rate, and bodyweight on differences in event rates. FINDINGS: We noted no temporal link between size of differences in blood pressure and different event rates. Serial mean matching for differences in systolic blood-pressure attenuated HRs for coronary and stroke events to a similar extent as did adjustments for systolic blood-pressure differences in Cox-regression analyses. HRs for coronary events and stroke adjusted for blood pressure rose from 0.86 (0.77-0.96) to 0.88 (0.79-0.98) and from 0.77 (0.66-0.89) to 0.83 (0.72-0.96), respectively. Multivariate adjustment gave HRs of 0.94 (0.81-1.08) for coronary events (HDL cholesterol being the largest contributor) and 0.87 (0.73-1.05) for stroke events. INTERPRETATION: Multivariate adjustment accounted for about half of the differences in coronary events and for about 40% of the differences in stroke events between the treatment regimens tested in ASCOT-BPLA, but residual differences were no longer significant. These residual differences could indicate inadequate statistical adjustment, but it remains possible that differential effects of the two treatment regimens on other variables also contributed to the different rates noted, particularly for stroke.

Adult↗

PubMed2000

Optic nerve head appearance in juvenile-onset chronic high-pressure glaucoma and normal-pressure glaucoma.

OBJECTIVE: To evaluate the appearance of the optic nerve head in chronic high-pressure glaucoma and normal-pressure glaucoma. DESIGN: Clinic-based cross-sectional study. PARTICIPANTS: The study included 52 eyes with normal-pressure glaucoma and 28 eyes with juvenile-onset primary open-angle glaucoma that served as models for chronic high-pressure glaucoma. METHODS: Color stereo optic disc photographs and wide-angle retinal nerve fiber layer photographs were morphometrically examined. MAIN OUTCOME MEASURES: Localized retinal nerve fiber layer defects; parapapillary chorioretinal atrophy; disc hemorrhages; optic cup shape; retinal arteriole narrowing. RESULTS: Both study groups did not vary significantly in count of localized retinal nerve fiber layer defects, size of parapapillary atrophy, optic cup depth, steepness of disc cupping, rim/disc area ratio, diameter of retinal arterioles, and frequency and degree of focal retinal arteriole narrowing. In normal-pressure glaucoma versus juvenile open-angle glaucoma, localized retinal nerve fiber layer defects were significantly broader, disc hemorrhages were found significantly more often and were larger, and neuroretinal rim notches were present more frequently and were deeper. CONCLUSIONS: Chronic high-pressure glaucoma and normal-pressure glaucoma show morphologic similarities in the appearance of the optic nerve head. The lower frequencies of detected disc hemorrhages and rim notches in high-pressure glaucoma may be due to a smaller size of hemorrhages and localized retinal nerve fiber layer defects in high-pressure glaucoma. Both glaucoma types have morphologic features in common, suggesting that they may possibly belong to a spectrum of the same pathologic process.

Adolescent↗

PubMed1996

Measurement of variceal pressure with an endoscopic pressure sensitive gauge: validation and effect of propranolol therapy in chronic conditions.

AIM/METHODS: Variceal pressure was measured at endoscopy in 98 patients with a non-invasive, pressure-sensitive gauge technique. RESULTS: In nine patients undergoing sclerotherapy, the values obtained correlated closely with those determined by fine-needle puncture of the varices (r = 0.95, p < 0.001). In 15 patients receiving placebo as part of a double-blind, placebo-controlled prospective evaluation of prophylactic treatment with propranolol, variceal pressure did not change significantly over a 1-year period: 16.5 +/- 3.2 mmHg at onset: 16.7 +/- 3.4 after 3 months and 15.9 +/- 3.5 after 12 months. In contrast, propranolol therapy given to 15 patients decreased the pressure from 16.2 +/- 3.0 mmHg before therapy to 13.5 +/- 2.0 after 3 months (p < 0.001) and to 13.1 +/- 4.1 after 12 months (p < 0.05). Patients with a recent bleeding episode had higher pressures than those who had not yet experienced any haemorrhage (19.3 +/- 3.5 mmHg, n = 17 vs 13.9 +/- 3.3, n = 62) (p < 0.001). This was confirmed in a prospective study: the last variceal pressure in bleeders and non-bleeders was respectively 17.2 +/- 1.7 mmHg (n = 4) and 14.8 +/- 4.1 mmHg (n = 26) (p < 0.01). Overall, variceal pressure measurements correlated with the size of varices, the presence of red colour signs and with the North Italian Endoscopic Club score. CONCLUSIONS: This study has shown that the non-invasive pressure gauge Varipress represents a reproducible method to regularly assess variceal pressure, an important parameter related to the risk of bleeding, and to assess the effects of pharmacological therapy with propranolol.

Adrenergic beta-Antagonists↗

PubMed2003

[Protocol to evaluate automatic continuous positive airway pressure. Assessment of the usefulness of the Autoset-T device to determine optimal pressure for treating sleep apnea/hypopnea syndrome].

INTRODUCTION: Given the high prevalence of sleep apnea/hypopnea syndrome (SAHS) and great demand for conventional polysomnography (PSG) and long waiting lists, alternative means for diagnosing SAHS and titrating continuous positive airway pressure (CPAP) are needed. Automatic CPAP may play a role in meeting the last objective, not only for treatment but also for suggesting the optimum CPAP setting. OBJECTIVES: a) To define a protocol to assess the functioning of an automatic CPAP device by means of a mechanical model; b) to determine the behavior of automatically adjusted CPAP during PSG; c) to define the usefulness of automatic CPAP for indicating optimal CPAP pressure for patients with SAHS; d) to evaluate the efficacy of the automatically indicated pressure setting against conventional PSG. METHODS: Four protocols were carried out using the Autoset-T (AT) device. 1. Apneas, hypopneas, flow limitation, snoring and normal flow were simulated in a laboratory using a mechanical model in order to check AT functioning. 2. The behavior of the automatically adjusted CPAP was observed in real time during PSG in 12 patients with severe SAHS. 3. The agreement of CPAP titrated with the AT and with PSG was checked in a group of 39 patients with SAHS. 4. The efficacy of the CPAP pressure recommended by the AT was checked by PSG in a group of 14 patients with SAHS. RESULTS: With the AT, CPAP increased rapidly in response to apneas or snoring in the mechanical model and during conventional PSG; it took only a mean 2.8 3.1 min to rise from a baseline pressure of 4 cm H2O to a near-optimum pressure of 11 1 cm H2O. Once normal flow was reached CPAP slowly decreased, responding with great sensitivity to the slightest abnormality, especially snoring, but not changing in response to certain types of flow limitation. The pressure read visually on the AT was similar to the one recommended by PSG in most of the 39 patients (71%). The PSG performed after one month of using AT-recommended CPAP titration confirmed that the number of apneas, hypopneas (apnea/hypopnea index 6(1) and arousals (8 2) was normal for these SAHS patients. CONCLUSIONS: The AT increases pressure rapidly in the presence of respiratory events and maintains a normal breathing pattern in most patients. Visual reading of the AT pressure allows correct identification of the optimal CPAP setting for SAHS treatment.

Aged↗

PubMed2001

In vitro placental pressure-flow behaviour is non-linear and depends on the external pressure.

OBJECTIVE: To study pressure-flow behaviour of in vitro placentas under normal simulated conditions and during raised external pressures, to simulate in vivo placental hemodynamic function, and as a model for polyhydramnios and the supine hypotension syndrome. DESIGN: Eleven normal term human singleton in vitro placentas were perfused under optimal physiologic conditions. Perfusion pressures varied between 5 and 90 mmHg, external pressures between 4 and 30 mmHg. Venous-external pressure (mmHg) combinations included 10-4, 10-10, 20-20, 25-25, 30-30 and 10-20. RESULTS: Pressure-flow curves varied markedly among the 11 placentas, but all showed a non-linear, perfusion pressure-dependent resistance. The in vitro placental resistances were significantly higher than estimated in vivo values. All placentas showed inevitable leakage at the maternal side due to damage during delivery. Increased external pressures increased the placental resistance at lower perfusion pressures. CONCLUSION: Placental damage reduces the number of perfused cotyledonic capillaries. This increases the placental resistance but preserves circulatory properties. Our findings therefore, represent in vivo placental function. They may explain why polyhydramnios often persists and that polyhydramnios and the supine hypotension syndrome are likely to be more detrimental in hypotensive than in normotensive or hypertensive fetuses.

Adult↗

PubMed1997

A comparison of cardiac rate-pressure product and pressure-rate quotient with Holter monitoring in patients with hypertension and cardiovascular disease: a follow-up report.

OBJECTIVES: The purpose of this study was to evaluate patients with hypertension or cardiovascular disease, or both, for myocardial ischemia and cardiac arrhythmias while undergoing minor oral surgery. STUDY DESIGN: Sixteen patients were studied with noninvasive monitoring including heart rate, systolic, diastolic, and mean arterial blood pressure to calculate rate-pressure product (systolic blood pressure multiplied by heart rate) and pressure-rate quotient (mean arterial pressure divided by heart rate). These calculated measures were compared with the incidence of cardiac arrhythmias and ST segment depression recorded on a continuous Holter monitoring system. RESULTS: Nine of 16 (56%) developed supraventricular or ventricular ectopy during dental extractions or minor preprosthetic surgery performed with local anesthesia 2% xylocaine with 1/100,000 epinephrine dilution. Three of the nine patients who experienced these arrhythmias had coincident abnormal rate pressure product and pressure-rate quotient values. None of these patients exhibited ST-T wave changes suggestive of myocardial ischemia. Atrial or ventricular ectopy suggests that myocardial irritability was more likely to occur than ischemia as measured by Holter monitoring and compared with abnormal rate pressure product and pressure-rate quotient values recorded.

Adult↗

PubMed2003

Respiratory-related evoked potential and upper airway transmural pressure change by using the negative expiratory pressure (NEP) device.

OBJECTIVE: Several studies have previously shown respiratory related evoked potentials (RREP) in humans elicited by mechanical stimuli applied on upper airways (UA). According to us, heterogeneous findings, concerning latencies and amplitudes, have been reported because of the different timing of stimuli application during the respiratory cycle and/or features of pressure stimuli. Therefore we evaluated the cortical response evoked by transmural pressure changes at the mouth induced by a negative expiratory pressure (NEP) device. METHODS: RREP were recorded in 22 healthy non-obese, non-snoring volunteers. The subjects were studied awake in seated position during quiet breathing. Three different pressure levels were applied, in a random order, 200 ms after the beginning of expiration. Cortical electrical responses were recorded from scalp electrodes at Fz, Cz, and Pz scalp location (international 10-20 system) referenced to the linked earlobes. RESULTS: RREP responses consisted of two negative (N45, N120) and two positive (P22, P85) waves. There was no significant effect of pressure or electrode on component latencies. The P22 wave (PRESSURE: F(df 2,42)=6.66, P<0.01), the N45 wave (PRESSURE: F(df 2,42)=16.51, P<0.001), and the P85 wave (PRESSURE: F(df2,42)=15.15, P<0.001) increased significantly theyr amplitude with increasing from pressure stimuli 1 to 10 cmH2O. CONCLUSIONS: The present results suggest that the UA NEP application in humans is a reliable way of evoking cortical responses. The experimental features that we described allow us to minimize the confounding factors in evaluating RREPs. The NEP device appears to be a useful tool for investigation of the neurobiology of UA sensation in humans.

Adult↗

PubMed2006

Influence of childhood socioeconomic circumstances, height, and obesity on pulse pressure and systolic and diastolic blood pressure in older people.

This study assesses the association of childhood socioeconomic circumstances, height, and obesity with components of blood pressure. We selected 4009 people representative of the Spanish population aged 60 years and older, and estimated systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure (PP) according to childhood social class, height, and obesity. No association was found between childhood social class and blood pressure. SBP showed an inverse gradient and DBP a direct gradient with height, although an independent association between height and DBP was found only in women. Stature was independently associated with increased DBP in women with central obesity, but there was no association between height and DBP in women without central obesity. Short stature was independently associated with increased PP. Body mass index and waist-to-hip ratio were independently associated with increased DBP in women, and waist-to-hip ratio was independently associated with increased PP in men, while waist circumference was independently associated with increased DBP and increased PP in women. These results do not support the assumed effect of socioeconomic circumstances in early life on blood pressure, which may depend on the context and/or study population. The relations observed between height and blood pressure support the hypothesis that PP could be a mediator of the association between short stature and increased cardiovascular risk. The relationship between obesity measures and components of blood pressure reinforces the recommendation to reduce body weight in order to reduce blood pressure.

Adult↗

PubMed2000

Effects of pressure support ventilation and continuous positive airway pressure on diaphragm performance.

Many patients who are on mechanical ventilation are on ventilator modes called pressure support ventilation (PSV) and continuous positive airway pressure (CPAP) particularly when they are being weaned. As the diaphragm is responsible for approximately 75% of breathing, it is important to promote diaphragm shortening to optimize weaning from mechanical ventilation. The purpose of our 1998 quasi-experimental study was to explore the effects of PSV and CPVP on diaphragm shortening. An animal model was utilized using four Sprague-Dawley rats from the same litter purchased from Sasco (Kansas City, USA). Also measured in this study were intrathoracic pressure (DeltaITP), positive inspiratory pressure, respiratory rate, tidal volume, end-tidal carbon dioxide, central venous pressure (CVP) and mean arterial pressure (MAP). Pressure support was increased in increments of 5 cm H2O at CPAP levels of 0, 2 and 4 cm H2O. A direct assessment of diaphragm shortening was achieved through the adherence of a miniaturized ultrasonic sensor to the inferior surface of the middle costal surface of the right hemidiaphragm of four Sprague-Dawley rats. Limitations of this study included a small sample size, anaesthetized rats and abdominal dissection for insertion of the ultrasonic sensor. As PSV was increased, there was a decrease in MAP, CVP, respiratory rate and end-tidal CO2. When increasing levels of CPAP were added to PSV, a decrease in diaphragm shortening was observed. These results support that higher levels CPAP may hinder diaphragmatic function thus prolong mechanical ventilation. The purpose of this pilot study was to explore the effects of PSV and CPAP on diaphragm shortening. Also measured were DeltaITP, positive inspiratory pressure, respiratory rate, tidal volume, end-tidal carbon dioxide, CVP and MAP. Pressure support was increased in increments of 5 cm H2O at CPAP levels of 0, 2 and 4 cm H2O. A direct assessment of diaphragm shortening was achieved through the adherence of a miniaturized ultrasonic sensor to the inferior surface of the middle costal surface of the right hemidiaphragm of four Sprague-Dawley rats. Limitations of this study included a small sample size, anaesthetized rats and abdominal dissection for insertion of the ultrasonic sensor. As PSV was increased, there was a decrease in MAP, CVP, respiratory rate and end-tidal CO2. When increasing levels of CPAP were added to PSV, a decrease in diaphragm shortening was observed.

Animals↗

PubMed2006

Respiratory pressure monitoring as an indirect method of intra-abdominal pressure measurement in gastroschisis closure.

AIM OF STUDY: Abdominal compartment syndrome (ACS) is a rare but potentially fatal complication of gastroschisis closure. The liberal use of a staged reduction technique has become a well-established method of avoiding this problem. Unfortunately the use of silos is associated with a high rate of sepsis, prolonged ileus, and ventilation. A method of predicting an impending ACS would help surgeons to decide more objectively which patients would benefit from a staged reduction. A new simple method is presented here which predicts intra-abdominal pressure based on airway pressure readings. METHOD: Over a four-year period, 34 neonates with gastroschisis underwent measurement of Pplateau respiratory pressures and simultaneous intra-vesical pressures. RESULT: The Pplateau pressures were approximately 10 cmH2O higher than any concurrent intra-vesical pressure readings. ACS occurred, in one patient, when pressure measurements were above 15 cmH2O (intra-vesical) or 25 cmH2O (Pplateau). CONCLUSION: By measuring Pplateau pressures, it is possible to predict the intra-abdominal pressure and hence avoid the development of an abdominal compartment syndrome on closing the abdominal wall in gastroschisis.

Abdomen↗

PubMed1998

Is urinary bladder pressure a sensitive indicator of intra-abdominal pressure?

BACKGROUND AND STUDY AIMS: The accuracy of transurethral bladder catheter pressure in reflecting intra-abdominal pressure is well defined in experimental studies and case reports but not in controlled clinical trials. PATIENTS AND METHODS: We compared bladder pressure with insufflator pressure during laparoscopic cholecystectomy in 40 patients. Measurements were made at four pressure levels of the insufflator: 0, 5, 10 and 15 mmHg. RESULTS: When the insufflator displayed 0, 5, 10, and 15 mmHg (0, 6.8, 13.6 and 20.4 cmH2O), and the mean bladder pressures measured 2.5 +/- 1.4, 7.3 +/- 1.5, 12.9 +/- 1.6 and 19.7 +/- 1.5 cmH2O, respectively. The two measurements correlated well with each other (r = 0.973, P < 0.0001). CONCLUSION: We concluded that bladder pressure measured by transurethral catheter was equal to insufflator pressure during laparoscopy, and that this was a valid indicator of intra-abdominal pressure.

Abdomen↗

PubMedDate not supplied

[Contact surfaces, compressive forces and pressure distribution in osteosynthesis. Model studies using pressure-sensitive foil].

Previous pressure gauges have been unable to measure exactly the stress over the cross-section of fractures or osteotomies. This first became possible with the pressure sensitive foil. Known operative procedures were examined with this foil using a self-compressing plate and a synthetic tube model. Contact area, compressive force, pressure and pressure distribution were measured simultaneously and analogously. A straight plate produces extremely little force and pressure on the gap. Both are limited to about a quarter of the cross-section just below the plate. The consequence is no sufficient stability. Also, using a prebent plate results in inhomogeneous pressure distribution with high values, but a distinct decrease of the stress on the opposite side of the plate, especially by compression applied at the end of the plate. But compression from near the fracture side gives the highest values and a most homogeneous force distribution. In this case the force recorded 1700 N, the mean pressure 5,2 MPa and the contact 90% of the cross-section. The length thrust of the plate ends approximately at a torque of screw tightening at 1,0 Nm. Using torques up to 2,5 Nm, force and pressure increase isometrically. Higher torques have no influence. Converging screws result in smaller contact, force and pressure, because they produce a vector force away from the gap and a smaller length thrust.

Biomechanical Phenomena↗

PubMed2005

Middle ear pressure equilibration ability and spontaneous pressure changes in healthy ears with ventilation tubes.

CONCLUSION: The results of this study give support to the theory that opening the middle ear (ME) to the atmosphere leads to a deterioration in its pressure regulation capacity. However, this is probably not the reason why a perforation of the tympanic membrane becomes chronic. OBJECTIVE: Direct, continuous measurement is a method of studying ME pressure regulation. We found previously that subjects with chronic central perforation (CCP) had a negative ME pressure in the daytime, in contrast to subjects with healthy ears. In this study, in order to elucidate the cause of this negative pressure, measurements were performed in healthy ears with ventilation tubes (VTs). MATERIAL AND METHODS: A VT was inserted 1 week prior to the measurements in 18 subjects. A hearing protector was tightly fitted deep into the external ear canal and connected to a portable system consisting of a pressure transducer and a memory. RESULTS: The measurements revealed a mean ME pressure during the first 3 h of -27 daPa. Ten subjects showed an initial decrease in pressure leading to a considerable negative mean ME pressure and a poor ability to equilibrate pressure differences through the Eustachian tube, like the subjects with CCP.

Adolescent↗

PubMed1988

Do laboratory tests of blood pressure reactivity predict blood pressure changes during everyday life?

This study was undertaken to examine whether blood pressure reactivity measured in the controlled setting of a laboratory could be correlated with blood pressure changes occurring during daily life. The subjects were 164 untreated hypertensives with mild hypertension, all of whom had a 24-hour ambulatory blood pressure recording, during which their activities were unrestricted. One hundred thirteen performed a treadmill exercise test, and 51 performed two active coping tasks (playing a video game or mental arithmetic). Blood pressure was monitored at baseline and during the tasks. Significant correlations were observed between the absolute levels of pressure measured during the laboratory tests and ambulatory monitoring, but these were higher for the active coping tasks (r = 0.53 to 0.75) than the exercise testing (r = 0.26 to 0.46) and were no higher for pressures measured during the tasks than at baseline. Correlations between the changes of blood pressure during the laboratory tasks and the changes occurring during ambulatory monitoring were analyzed in three ways, using simple, multiple, and canonical correlations. In no case were these correlations substantively significant. We conclude that blood pressure reactivity measured in the laboratory may not be readily generalized to changes of pressure in everyday life, as measured by noninvasive ambulatory recorders.

Adult↗

PubMed1991

Blood pressure response during long-term treatment with magnesium is dependent on magnesium status. A double-blind, placebo-controlled study in essential hypertension and in subjects with high-normal blood pressure.

Both experimental and epidemiological studies support the idea of magnesium supplementation in essential hypertension. We added 15 mmol Mg to a free diet in 71 subjects with mild essential hypertension or a high-normal blood pressure in a double-blind, placebo-controlled study over 6 months. The treatment, which raised urinary magnesium excretion 30%, induced no general effects on the blood pressure. However, when the changes in blood pressure in the actively treated group were related to the pretreatment magnesium status, a correlation was found between pretreatment urinary magnesium excretion and the induced change in supine blood pressure (P less than .05) with a blood pressure reduction in subjects with a low pretreatment urinary excretion of magnesium, and a pressor effect in the subjects with the highest pretreatment levels of urinary magnesium. The induced change in blood pressure was furthermore found to be inversely correlated to the changes in serum magnesium and urinary excretion of sodium (P less than .03) induced by treatment indicating that both a direct calcium antagonist action of magnesium at the cellular level as well as a diuretic effect of the increased magnesium load might be involved in the blood pressure effects of magnesium. Pretreatment serum potassium concentration also appeared to be a predictor of the induced change in standing blood pressure (P less than .03). In conclusion, magnesium supplementation does not seem to be effective in unselected mild hypertensive subjects or in subjects with a high-normal blood pressure and can therefore not be generally recommended.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗

PubMed1991

Coronary pressure-flow, pressure-function, and function-myocardial oxygen consumption relations in postischaemic myocardium.

STUDY OBJECTIVE: The aim was to study coronary pressure-flow, pressure-myocardial wall motion and myocardial wall motion-myocardial oxygen consumption relations in postischaemic myocardium with prolonged myocardial dysfunction (stunned myocardium) in comparison with normal myocardium. DESIGN: Regional myocardial wall thickening was measured with ultrasonic crystals, and postischaemic myocardial dysfunction was achieved by occlusion of a carotid-left anterior descending coronary artery bypass (15 min) and reperfusion (30 min). Coronary perfusion pressure was decreased in 10 mm Hg steps by constricting the bypass before and after producing postischaemic myocardial dysfunction. At each constriction step, coronary flow, regional wall thickening, and regional myocardial oxygen consumption in the area perfused by the left anterior descending artery were measured. EXPERIMENTAL MATERIAL: 12 anaesthetised open chest mongrel dogs, weighing 12-16 kg, were studied. MEASUREMENTS AND MAIN RESULTS: At the basal level, myocardial wall thickening of postischaemic myocardium was depressed compared to normal myocardium, at 18.5(SD 8.9)% v 1.3(7.1)%, p less than 0.01. With coronary stenosis, wall thickening gradually decreased at a coronary pressure below 60 mm Hg in normal myocardium, but remained unchanged until mean coronary pressure was reduced to 50 mm Hg in postischaemic myocardium. Myocardial wall thickening of postischaemic myocardium was always more depressed than normal myocardium. At any level of coronary pressure, coronary flow in postischaemic myocardium was not different from normal myocardium. There was no difference in regional myocardial oxygen consumption between normal and postischaemic myocardium at any level of coronary pressure. However, regional myocardial oxygen consumption in postischaemic myocardium was higher than in normal myocardium performing similar levels of myocardial wall thickening. CONCLUSION: The coronary pressure-function relation but not the pressure-flow relation changed in postischaemic myocardium after a 15 min coronary occlusion. Regional myocardial oxygen consumption was relatively increased in postischaemic myocardium.

Animals↗

PubMed2005

Influence of short stature on the change in pulse pressure, systolic and diastolic blood pressure from age 36 to 53 years: an analysis using multilevel models.

BACKGROUND: Previous cross-sectional analyses of this cohort have shown that short height and leg length are associated with higher pulse pressure and systolic blood pressure in middle age. It is unclear how these adult measures of childhood growth influence the change in blood pressure as it increases with age. METHODS: Multilevel models were fitted to investigate associations between components of height and the change in blood pressure between 36, 43, and 53 years in a prospective national cohort of 1472 men and 1563 women followed-up since birth in 1946. RESULTS: Shorter height and leg length, but not trunk length, were associated with higher blood pressure, similarly in men and women. Longitudinal analyses showed that the effects of both height and leg length on pulse pressure and systolic blood pressure became significantly stronger with age. For example, the change in systolic blood pressure was found to be -0.021 mm Hg (95% confidence interval -0.029 to -0.013) per year lower for every centimetre increase in leg length (P < or = 0.001). In other words, the increase in systolic blood pressure over a 10 year period of a participant whose legs were 10 centimetres shorter was 2.1 mm Hg higher (P < or = 0.001), compared with a taller participant. Associations were independent of a number of potential confounders. CONCLUSIONS: These results support the hypothesis that short people may be more susceptible to the effects of ageing on the arterial tree. Childhood growth may contribute to the tracking of cardiovascular risk throughout life.

Adult↗