Systolic Arterial Pressure Values Research Articles

English

Introduction Fifty-two American Society of Anesthesiologists II-III patients undergoing elective coronary artery bypass surgery were included in the study. Materials and methods We examined haemodynamic and cerebral responses to induction and intubation in cardiac surgery using different doses of an opioid. Before induction, T1 values of systolic arterial pressure, mean arterial pressure, diastolic arterial pressure, heart rate, saturation, bispectral index, latencies of auditory evoked potential waves (V. wave, Na wave, Pa wave and Nb wave) and spectral edge frequency values were measured. The patients were divided into four groups, each comprising 13 individuals. During induction, the patients were administered opioids as follows: Group 1: propofol 2.5 mg/kg + rocuronium 0.7 mg/kg Group 2: propofol 2.5 mg/kg + rocuronium 0.7 mg/kg + fentanyl 3 mcg/kg Group 3: propofol 2.5 mg/kg + rocuronium 0.7 mg/kg + fentanyl 6 mcg/kg Group 4: propofol 2.5 mg/kg + rocuronium 0.7 mg/kg + fentanyl 9 mcg/kg Above-mentioned parameters were repeated in the first minute of induction (T2). Intubation was performed in the third minute of induction, then the measurements were repeated (T3). Results Demographics were similar among all four groups. According to the systolic arterial pressure, mean arterial pressure, diastolic arterial pressure and heart rate values, a significant increase was found in group 1 compared to group 4 at T3. There was also a significant difference between group 1 and group 3 in mean arterial pressure and heart rate measures. No significant difference was found between the groups in terms of bispectral index. There was also no significant difference between the groups in terms of spectral edge frequency1-2. Auditory evoked potential wave latencies (V. wave, Na wave, Pa wave, Nb wave) were found to be different between the time intervals. Wave latencies were increased at T2 compared to T1 and decreased at T3 compared to T2 in all the groups. The statistically significant difference was found between fentanyl 0 group and fentanyl 9 mcg/kg group in terms of Nb wave latency values. Conclusion Auditory evoked potential is found to be more reliable than bispectral index and electroencephalogram with regards to the responses to induction and intubation using fentanyl. We also observed that Nb wave latency response is the most significant latency of auditory evoked potential waves. Introduction Recently, various techniques and tools have been introduced in order to be aware of the adverse haemodynamic effects that may arise due to insufficient or overdose of anaesthetic agents and also to avoid economic losses1. Electroencephalogram (EEG), bispectral index (BIS) analysis and auditory evoked potentials (AEPs) are the monitorisation methods developed to determine the intraoperative anaesthetic depth. In this study, haemodynamic and cerebral effects during induction and intubation were evaluated using BIS, AEP and EEG in patients who are undergoing coronary artery bypass surgery. Materials and methods This work conforms to the values laid down in the Declaration of Helsinki (1964). The protocol of this study has been approved by the relevant ethical committee related to our institution in which it was performed. All subjects gave full informed consent to participate in this study. After local ethic committee approval, 52 patients aged > 18 years, American Society of Anesthesiologists (ASA) II-III, undergoing elective coronary artery bypass surgery were included in the study. Exclusion criteria were as follows: ejection fraction (EF) 2 mg/dL, aspartate aminotransferase > 40 U/L, alanine aminotransferase > 40 U/L, hematocrit < 30%), opioid and propofol * Corresponding author Email: drozkanonal@selcuk.edu.tr 1 TurkiyeYuksekIhtisas Education and Research Hospital, Anesthesia Clinic, Ankara, Turkey 2 Medical Faculty, Anesthesia and Reanimation Department, Selcuk University, Konya, Turkey

Non-invasive continuous arterial pressure measurement based on radial artery tonometry in the intensive care unit: a method comparison study using the T-Line TL-200pro device

BackgroundThe T-Line TL-200pro (TL-200pro) device (Tensys Medical, Inc., San Diego, CA, USA), based on radial artery tonometry, provides an arterial pressure (AP) waveform and beat-to-beat values of systolic arterial pressure (SAP), mean arterial pressure (MAP), and diastolic arterial pressure (DAP). The aim of the study was to evaluate this non-invasive technique for continuous AP monitoring in medical intensive care unit (ICU) patients. MethodsArterial pressure measurements obtained using the TL-200pro technology were compared using Bland–Altman analysis with values measured directly from a femoral arterial catheter in 34 ICU patients. ResultsArterial pressure values were analysed and compared in 4502 averaged 10-beat epochs. A bias of +0.72 mm Hg (95% limits of agreement −9.37 to +10.82 mm Hg) was observed for MAP. For SAP and DAP, there was a mean difference of −1.39 mm Hg (95% limits of agreement −18.74 to +15.96 mm Hg) and +4.36 mm Hg (95% limits of agreement −8.66 to +17.38 mm Hg), respectively. The percentage error for MAP, SAP, and DAP was 12%, 14%, and 21%, respectively. ConclusionsArterial pressure measurement based on radial artery tonometry using the TL-200pro technology is feasible in medical ICU patients. The TL-200pro system is capable of providing MAP values with high accuracy (low mean difference) and precision (narrow limits of agreement) compared with MAP measured invasively using a femoral arterial catheter. The TL-200pro technology is promising for the measurement of SAP and DAP but further development is necessary to improve accuracy and precision.

Effects of Thiopental, Propofol, Etomidate, Midazolam on Hemodynamic in Anesthesia Induction and Intubation of Hypertensive Patients in the Coronary Artery Bypass Grafting Surgery

Objective: The purpose of this study is to compare the hemodynamic effects of thiopental, propofol, etomidate, midazolam on induction of anesthesia, laryngoscopy, and endotracheal intubation of hypertensive patients who will undergo coronary artery bypass grafting (CABG) surgery.Material and Methods: A total of 80 patients with chronic hypertension, aged between 40 and 75 who are to undergo CABG surgery were included in a prospective, single-blind, and randomized study. Group T received thiopental sodium (5-7 mg kg), Group E etomidate (0.2 - 0.5 mg kg), Group P propofol (1 - 2.5 mg kg ), and Group M midazolam (0.1 - 0.4 mg kg) anesthetic agents. The induction was achieved by using fentanyl and rocuronium in all groups. Heart rate (HR), systolic arterial pressure (SAP),diastolic arterial pressure (DAP), mean arterial pressure (MAP) were recorded for the first 15 minutes. Also arterial blood gases (ABG) were sampled, and partial arterial carbon dioxide (aCO) values were recorded.Results: SAP values decreased prior to laryngoscopy in Group T, E, and P. Only in Group E, increase in SAP during laryngoscopy and tracheal intubation was statistically significant. The decrease in MAP was significant in only Group T. At 15 minutes of intubation increases in MAP and HR in Group P was also statistically significant.Conclusion: We think that the safest induction of anesthesia during laryngoscopy, and endotracheal intubation in hypertensive patients who will undergo CABG surgery will be acvhieved with midazolam (Group M)

Polimorfismo 3’UTR +62G>A del gen RETN codificante de resistina y asociación con componentes del síndrome metabólico

Background and objectiveThe polymorphism of the resistin gene (RETN/RSTN) has been associated with metabolic alterations. In this study the association between the 3’UTR +62G>A polymorphism and metabolic syndrome components was evaluated. Subjects and methodsThe population (n=218) was distributed in 3 groups: the control group with no metabolic alterations (n=77), nSMA group with isolated metabolic alterations (n=94) and MS group with metabolic syndrome (n=47). The 3’UTR +62G>A polymorphism was analyzed by PCR-RFLP. ResultsCentral obesity was the most frequent alteration in both nSMA (56.4%) and MS (91.5%) groups followed by low c-HDL levels in the nSMA group (42.6%) and arterial hypertension in the MS group (85%). The frequency of the +62G/A genotype was 20.2% in the population. The G/A genotype was more frequently found in the MS (38.3%) and nSMA (17%) groups than in the control group (13%). The allelic distribution between the control group (+62G=0.94, +62A=0.06) and MS group (+62G=0.81, +62A=0.19) was significantly different (P=.0001). Significant associations between the G/A genotype and high values of abdominal circumference (P=.047), basal glycemia (P=.02) and systolic arterial pressure (P=.003) were found. ConclusionThe findings suggest the association between the G/A genotype and high values of systolic arterial pressure, basal glycemia and abdominal circumference. This association was independent of the metabolic syndrome context.

Alterations of baroreflex sensitivity after carotid endarterectomy according to the preoperative carotid plaque echogenicity

Baroreflex sensitivity is lower in patients with echogenic carotid plaques compared with patients with echolucent ones. The purpose of our study was to compare the baroreflex function after carotid endarterectomy (CEA) between patients with different plaque echogenicity. Spontaneous baroreflex sensitivity (sBRS), heart rate, and systolic and diastolic arterial pressure were calculated in 51 patients with a severe carotid stenosis (70%-99%) 24 hours before CEA, as well as 24 and 48 hours after CEA. Carotid plaque echogenicity was graded from 1 to 4 according to Gray-Weale classification, after duplex examination, and the patients were divided into two groups: the echolucent (grade 1 or 2) and the echogenic (grade 3 or 4). The postoperative mean systolic arterial pressure values in all 51 patients at 24 and 48 hours (143.2 and 135.5 mm Hg, respectively) were found to be significantly increased compared with the preoperative value (132.5 mm Hg; x2=32, P<.001). Mean sBRS value, in all patients, was significantly reduced postoperatively to 2.1 ms mm Hg(-1), from the mean preoperative value, 3.7 ms mm Hg(-1), independently of plaque echogenicity. Twenty patients (39%) were included in the echolucent group and 31 (61%) in the echogenic. The two groups had significant differences in two parameters: the rate of diabetes mellitus and the rate of symptomatic plaques. After adjusting the two groups for these differences, we found that the preoperative difference in sBRS between the two groups (F[1,51]=11, P<.003) was eliminated 24 and 48 hours after CEA (F[1,51]=.007, P<.9 and F[1,51]=.4, P<.5 for 24 and 48 hours, respectively). Before the removal of carotid atheroma, baroreflex sensitivity, which is a well established cardiovascular risk factor, seems to be affected by carotid plaque echogenicity. However, CEA has as a result a similar baroreflex response in all patients, regardless of plaque echogenicity, implying no association of plaque morphology and postoperative baroreflex sensitivity.

Altered cardiovascular autonomic regulation in overweight children engaged in regular physical activity

Overweight (OW) and obesity in children are important forerunners of cardiovascular risk, possibly through autonomic nervous system (ANS) dysregulation, while physical exercise exerts a beneficial influence. In this observational study...

Effect of ramadan fasting on renal function markers and serum electrolytes after a rugby sevens match

–The effect of Ramadan fasting on renal function markers, serum electrolytes and cardiovascular parameters at basal conditions and after a simulation of a rugby sevens match was studied in twelve recreational rugby sevens players. Three matches were played: one day before Ramadan (before Ramadan), at the end of the first week of Ramadan (Beg-R) and at the end of Ramadan (End-R). Before and immediately after each match, subjects provided a fasting blood sample for the measurement of hematological parameters and serum biochemistry. In addition, systolic arterial pressure (SAP) and diastolic arterial pressure (DAP) were measured. At rest, players experienced an increase in the following parameters from before Ramadan to End-R: urea (+9.9%, p<0.001), uric acid (+15.2%, p<0.001), creatinine (+22.4%, p<0.001), sodium (+2.9%, p<0.001), and chloride (+2%, p<0.001). Following the competition, players experienced an increase in the following parameters from before Ramadan to End-R: urea (+8.7%, p<0.05), uric acid (+15.2%, p<0.001), creatinine (+17.1%, p<0.001), sodium (+3.2%, p<0.001) and chloride (+2.9%, p<0.001). Post match values of SAP were significantly higher at End-R compared to the control period (p<0.05).The percentage of change of all biochemical and cardiovascular parameters in response to matches remained unchanged over the whole period of the investigation. We conclude that at basal conditions, the state of dehydration induced by Ramadan fasting was implicated in the increase of renal function markers values and serum electrolytes. Also, rugby sevens match played during Ramadan did not exacerbate the magnitude of responses to matches of biochemical and cardiovascular

Síndrome metabólico y complicaciones cardiovasculares en el paciente hipertenso

Background and objectivesThe aim of this study was to assess the impact of metabolic syndrome (MS) as a predictor of cardiovascular events (CVE) in hypertensives in primary prevention. Patients and methodsThis retrospective study involved 2410 non-diabetic, hypertensive patients (52% women, 43% with MS), without previous CVE. The total follow-up was 13096 patient-years with a median of 4,5 years (IIQ; 2,2-7,3). ResultsPatients with metabolic syndrome did not have more risk of CVE (HR 1,19; CI 95%:0,89-1,58; p=0,292), 183 patients had a CVE, 88 in patients with MS (15,4; CI 95%:12,4-19,0 patients-years), and 95 in patients without MS (13,0; CI 95%:10,5-15,9 patients/years) (p=0,279). In a multivariate analysis corrected for other factors, only age (HR 1,08; CI 95%: 1,07-1,10; p=0,001), male gender (HR 1,77; CI 95%: 1,27-2,45; p=0,001), smoking (HR 2,95; CI 95%: 2,01-4,34; p=0,001) at the beginning, and values of systolic arterial pressure ≥160mm Hg (HR 1,83; CI 95%: 1,17-2,89; p=0,009) and cholesterol-low density lipoproteins ≥160mg/dl (HR 1,58; CI 95%: 1,05-2,38; p=0,029) during the follow-up, were associated with new CVE. ConclusionsIn hypertensive non-diabetic patients in primary prevention the diagnosis of metabolic syndrome did not add any significant prediction about future CVE over the traditional risk factors. Systolic arterial pressure ≥160mm Hg and cholesterol-low density lipoproteins ≥160mg/dl, respectively, during the follow up were factors related to new CVE.

Cardiovascular responses to laryngoscopy and tracheal intubation are not accompanied by ST-segment changes

Cardiovascular responses to laryngoscopy and tracheal intubation are not accompanied by ST-segment changes

Symbolic analysis detects alterations of cardiac autonomic modulation in congestive heart failure rats

Congestive heart failure (CHF) is associated with neurohumoral activation. Only very few studies have examined the progression of autonomic dysfunction in CHF in humans and scanty data are available in animal models of CHF. This study was performed to assess the changes in cardiac autonomic modulation during the progression of CHF in a rat model, using an innovative analysis of heart rate variability. Progression of cardiovascular autonomic dysfunction was assessed in a rat model of CHF induced by coronary artery ligation. Spectral and symbolic analyses were performed on heart period (approximated with pulse interval, PI) and systolic arterial pressure (SAP) signals, acquired ~2 and ~4 weeks after the surgical procedure. As CHF developed, symbolic analysis revealed a decrease of rhythmical physiological sympathetic modulation, as indicated by the reduction of the percentage of stable patterns. In addition, symbolic analysis revealed that runs of short–long–short and/or long–short–long PI values and high–low–high and/or low–high–low SAP values were more and more frequent as CHF progressed. On the contrary, spectral analysis of PI and SAP series was not able to detect any impairment of autonomic regulation. Indeed, low frequency and high frequency powers derived from both PI and SAP series were not significantly changed. These data indicate that the autonomic cardiovascular modulation is altered during the progression of CHF and that symbolic analysis seems to be more suitable than spectral analysis to describe alterations of heart period dynamics and of cardiovascular regulation in this animal model of CHF.

Landiolol, a new ultra-short-acting β1-blocker, reduces anaesthetic requirement during sevoflurane/N2O/fentanyl anaesthesia in surgical patients

It is known that esmolol, a short-acting beta1-blocker, reduces anaesthetic requirement. In this study, we evaluated whether a low dose of landiolol, a new ultra-short-acting beta1-blocker, can reduce the sevoflurane requirement. Twenty-five patients undergoing hip surgery were randomly divided into two groups. Group A (n = 13) received landiolol (bolus injection of 0.031 mg.kg(-1) and continuous infusion at a rate of 0.01 mg.kg(-1).min(-1)). Group B (n = 12) received physiological saline. Landiolol and physiological saline were started before the induction of anaesthesia and continued until the end of anaesthesia. Anaesthesia was maintained with sevoflurane, 60% N(2)O and fentanyl. Sevoflurane concentration was controlled to keep the bispectral index at approximately 50. The end-tidal sevoflurane concentration and haemodynamics were measured during anaesthesia. The average end-tidal sevoflurane concentration in group A was significantly lower than that in group B (1.2 +/- 0.30 vs. 1.8 +/- 0.3%, P < 0.01). Maximum values of systolic arterial pressure showed no difference between the groups, whereas the maximum value of heart rate in group A was significantly less than that in group B (61 +/- 10 vs. 76 +/- 14 beats min(-1), P < 0.05). The results suggest that a low dose of landiolol significantly reduces the intraoperative sevoflurane requirement during sevoflurane/N(2)O/fentanyl anaesthesia in patients undergoing hip surgery.

Respostas cardiovasculares durante a postura sentada da Reeducação Postural Global (RPG)

OBJETIVO: Avaliar as respostas da frequencia cardiaca (FC), pressao arterial sistolica (PAS), diastolica (PAD), media (PAM) e duplo produto (DPr), durante a postura sentada do metodo de Reeducacao Postural Global (RPG). MATERIAIS E METODOS: Nove voluntarias saudaveis (23±2,1 anos, 56,4±7,8kg, 1,61±0,05m, 21,6±2,4kg.m2-1), inexperientes na pratica do metodo RPG, foram submetidas a uma sessao de RPG na postura sentada, realizada em tres fases: repouso pre-postura, execucao da postura e recuperacao pos-postura. No repouso e na recuperacao, as voluntarias permaneceram sentadas por 20 minutos, sendo PA e FC verificadas a cada cinco minutos. A fase de execucao da postura foi realizada em tres series e mantida por tres minutos cada, com intervalo de um minuto entre elas. A verificacao da PA e da FC foi realizada a cada um minuto e 30 segundos de execucao da postura. RESULTADOS: Os valores de PAS, PAD, PAM e DPr foram significativamente maiores (p<0,05) do terceiro ao nono minuto da execucao da postura (154±14, 107±11, 122±9mmHg e 16.478±2.802mmHg.min-1) quando comparados aos valores de repouso pre-postura (109±10, 74±7, 85±8mmHg e 9.374±1.687mmHg.min-1) e aos valores de recuperacao pos-postura. Porem, estes valores retornaram aos valores de repouso nos primeiros cinco minutos de recuperacao pos-postura. Durante a execucao da postura, a FC nao foi estatisticamente diferente da FC de repouso pre-postura. CONCLUSOES: Elevacoes significativas da PAS, PAD, PAM e DPr foram observadas durante a execucao da postura sentada da RPG empregada nesse estudo, mas retornaram aos valores de repouso nos primeiros cinco minutos de recuperacao pos-postura.

The prognostic value of haemodynamic parameters in the recovery phase of an exercise test. The Finnish Cardiovascular Study

We tested the hypothesis that the change from the peak to recovery values of systolic arterial pressure (SAP recovery) and rate-pressure product (RPP recovery) can be used to predict all-cause and cardiovascular mortality, as well as sudden cardiac death (SCD) in patients referred to a clinical exercise stress test. As a part of the Finnish Cardiovascular Study (FINCAVAS), consecutive patients (n=2029; mean age+/-SD=57+/-13 years; 1290 men and 739 women) with a clinically indicated exercise test using a bicycle ergometer were included in the present study. Capacities of attenuated SAP recovery, RPP recovery and heart rate recovery (HRR) to stratify the risk of death were estimated. During a follow-up (mean+/-s.d.) of 47+/-13 months, 122 patients died; 58 of the deaths were cardiovascular and 33 were SCD. In Cox regression analysis after adjustment for the peak level of the variable under assessment, age, sex, use of beta-blockers, previous myocardial infarction and other common coronary risk factors, the hazard ratio of the continuous variable RPP recovery (in units 1000 mm Hg x b.p.m.) was 0.85 (95% CI: 0.73-0.98) for SCD, 0.87 (0.78-0.97) for cardiovascular mortality, and 0.87 (0.81 to 0.94) for all-cause mortality. SAP recovery was not a predictor of mortality. The relative risks of having HRR below 18 b.p.m., a widely used cutoff point, were as follows: for SCD 1.28 (0.59-2.81, ns), for cardiovascular mortality 2.39 (1.34-4.26) and for all-cause mortality 2.40 (1.61-3.58). In conclusion, as a readily available parameter, RPP recovery is a promising candidate for a prognostic marker.

Differences in heart rate variability during haemodialysis and haemofiltration

The aim of our study was to evaluate whether convective (haemofiltration, Hf) and diffusive (haemodialysis, Hd) dialysis techniques induce different patterns of long- and short-term autonomic adjustments in haemodynamically stable dialysis patients. Ten haemodynamically stable Hd patients were studied. Each patient underwent a block of six Hd sessions, then was switched to six Hf. During the last session of each dialytic treatment, continuous beat to beat measurements of systolic arterial pressure (SAP) and heart rate (HR) were performed. Spectral analysis of heart rate variability (HRV) was made before and during the treatment to evaluate the modification of autonomic nervous system activity. Baseline values of plasma sodium, body weight, HR and SAP were not different for the two considered methods of dialysis, while the baseline values of normalized LF were significantly higher in Hf as compared to Hd and the opposite was observed for HF powers (P < 0.001). Sodium balance and body weight loss per hour did not differ between Hd and Hf while body temperature was kept constant in all sessions. Throughout the dialytic procedures, with both techniques, SAP was constant, while HR diminished from the first hour till the end of the procedure (P < 0.05). An increase in LF (and decrease in HF) was noticed only in the case of Hd, considering normalized units (P < 0.05). These selective changes were maintained also during the recovery after the procedure. The spectral analysis of RR interval variability during Hd and Hf suggests a potential autonomic advantage with Hf, to be added to the well-recognized intrinsic greater haemodynamic stability.

DOENÇAS CARDIOVASCULARES: PERFIL DE TRABALHADORES DO SEXO MASCULINO DE UMA DESTILARIA DO INTERIOR PAULISTA

The study presents the profile of 123 workers from a distillery, with regard to the risk factors of cardiovascular diseases. The results disclose 10,6% of the workers with level-1 obesity, 17,0% had level-2 obesity, 11,4% with systolic arterial pressure values ³ 140 mmHg, 12,2% with diastolic arterial pressure values ³ 90 mmHg, 60,2% had incomplete elementary school education, 40,7% reported the habit to perform physical activity, 16,3% were smokers, 65,9% indicated the consumption of alcoholic beverages and 49,6% reported to ingest salt in excess. Concerning their family history, 32,5% reported a family history with the pressure of hypertensive disease, 26,0% for cerebral vascular accidents and 27,6% for diabetes mellitus. Key words: Cardiovascular illnesses; Risk factors; Arterial hypertension.

Bradycardia and hypertension in anticipation of, and exacerbated by, peribulbar block: a prospective audit

Changes in heart rate (HR), systolic arterial pressure (SAP) and diastolic arterial pressure (DAP) occur in anticipation of, and following, injection of a peribulbar local analgesic agent. We examined these changes in two groups of awake patients given a pre-medication of either hydroxyzine 1.0 mg/kg alone (control) or hydroxyzine 1.0 mg/kg with morphine 0.05 mg/kg. HR, SAP and DAP of 100 patients per group were monitored the day before surgery (baseline), every 5 min in the anesthesia holding room before peribulbar injection, every minute for the first 5 min after peribulbar injection and then every 5 min until transfer to the operating room. Within and between pre-medication group values of HR, SAP and DAP before and after peribulbar injection were compared with baseline. The two groups of patients were similar. Before peribulbar injection, HR was unchanged in the hydroxyzine group, but 6% slower in those given morphine (P<0.01). After injection, HR slowed in both groups, by 5% and 7% (P<0.01, both comparisons), respectively. In anticipation of injection, SAP increased in both groups to 20% and 16% above baseline, respectively, and increased further after injection to 26% and 24% above baseline, respectively (P<0.001, all comparisons). In both groups, maximum SAP following injection exceeded maximum SAP before injection (P<0.02, both comparisons). DAP increased by 4% (P<0.05) in the hydroxyzine group before injection, and by 5% and 4%, respectively (P<0.005 and P<0.05, respectively) after peribulbar injection. The audit reveals pronounced increases in SAP accompanied by lesser increases in DAP and a tendency to slowing of HR in awake patients in anticipation of peribulbar injections. Peribulbar injections cause further increases in blood pressure and mild bradycardia. These changes occur similarly in patients pre-medicated with hydroxyzine or hydroxyzine plus morphine. A mix of neuro-humoral influences (anxiety/catecholamine/baroreceptor/trigemino-vagal) are postulated as etiological.

Association of Systemic Hypertension with Renal Injury in Dogs with Induced Renal Failure

Systemic hypertension is hypothesized to cause renal injury to dogs. This study was performed on dogs with surgically induced renal failure to determine whether hypertension was associated with altered renal function or morphology. Mean arterial pressure (MAP), heart rate (HR), systolic arterial pressure (SAP), and diastolic arterial pressure (DAP) were measured before and after surgery. Glomerular filtration rate (GFR) and urine protein: creatinine ratios (UPC) were measured at 1, 12, 24, 36, and 56–69 weeks after surgery, and renal histology was evaluated terminally. The mean of weekly MAP, SAP, and DAP measurements for each dog over the 1st 26 weeks was used to rank dogs on the basis of MAP, SAP, or DAP values. A statistically significant association was found between systemic arterial pressure ranking and ranked measures of adverse renal responses. When dogs were divided into higher pressure and lower pressure groups on the basis of SAP, group 1 (higher pressure, n = 9) compared with group 2 (lower pressure, n = 10) had significantly lower GFR values at 36 and 56–69 weeks; higher UPC values at 12 and 56–69 weeks; and higher kidney lesion scores for mesangial matrix, tubule damage, and fibrosis. When dogs were divided on MAP and DAP values, group 1 compared with group 2 had significantly lower GFR values at 12, 24, 36, and 56–69 weeks; higher UPC values at 12 and 56–69 weeks; and higher kidney lesion scores for mesangial matrix, tubule damage, fibrosis, and cell infiltrate. These results demonstrate an association between increased systemic arterial pressure and renal injury. Results from this study might apply to dogs with some types of naturally occurring renal failure.

Association of systemic hypertension with renal injury in dogs with induced renal failure.

Systemic hypertension is hypothesized to cause renal injury to dogs. This study was performed on dogs with surgically induced renal failure to determine whether hypertension was associated with altered renal function or morphology. Mean arterial pressure (MAP), heart rate (HR), systolic arterial pressure (SAP), and diastolic arterial pressure (DAP) were measured before and after surgery. Glomerular filtration rate (GFR) and urine protein:creatinine ratios (UPC) were measured at 1, 12, 24, 36, and 56-69 weeks after surgery, and renal histology was evaluated terminally. The mean of weekly MAP, SAP, and DAP measurements for each dog over the 1st 26 weeks was used to rank dogs on the basis of MAP, SAP, or DAP values. A statistically significant association was found between systemic arterial pressure ranking and ranked measures of adverse renal responses. When dogs were divided into higher pressure and lower pressure groups on the basis of SAP, group 1 (higher pressure, n = 9) compared with group 2 (lower pressure, n = 10) had significantly lower GFR values at 36 and 56-69 weeks; higher UPC values at 12 and 56-69 weeks; and higher kidney lesion scores for mesangial matrix, tubule damage, and fibrosis. When dogs were divided on MAP and DAP values, group 1 compared with group 2 had significantly lower GFR values at 12, 24, 36, and 56-69 weeks; higher UPC values at 12 and 56-69 weeks; and higher kidney lesion scores for mesangial matrix, tubule damage, fibrosis, and cell infiltrate. These results demonstrate an association between increased systemic arterial pressure and renal injury. Results from this study might apply to dogs with some types of naturally occurring renal failure.

Role of endothelin-1 and thromboxane A2 in renal vasoconstriction induced by angiotensin II in diabetes and hypertension

Interactions among angiotensin II (Ang II), endothelin-1 (ET-1) and thromboxane A2 (TXA2) may play an important role in the regulation of renal function. The present study investigated the participation of TXA2 and ET-1 in the increase in renal vascular resistances (RVR) induced by Ang II, as well as the consequences of diabetes, hypertension, and the combination of both on this response. Isolated kidneys from male normoglycemic or streptozotocin-induced diabetic Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were used. The increase in perfusion pressure (PP) produced by Ang II was studied in the absence or presence of the TXA2 receptor antagonist, ifetroban, or the ETA/ETB receptor antagonist, PD145065. Systolic arterial pressure (SAP) was higher in SHR than in WKY, but diabetic rats (D) from each strain showed lower SAP values than their respective non-diabetic rats. Basal renal PP was higher in WKY and SHR than in WKY-D and SHR-D. Increases in renal PP produced by Ang II were comparable in the kidneys from all groups. Either ifetroban or PD145065 reduced the maximal Ang II response in all animals. The maximal inhibitory effect of ifetroban was higher (P<0.05) in WKY than in the other groups. However, the maximal inhibitory effect of PD145065 was lower in SHR than in the other groups. This study supports a role for ET-1 and TXA2 as mediators of the increase in renal vascular resistance produced by Ang II. These results indicate that the participation of ET-1 in the renal vasoconstriction produced by Ang II was reduced under hypertensive conditions, and that of TXA2 was reduced by both diabetes and hypertension.

Dietary sodium and target organ damage in essential hypertension

In addition to its widely contested influence on arterial pressure, dietary sodium may exert some nonpressure-related effects on left ventricular mass in humans. In the present study, we hypothesized that sodium intake (estimated by two consecutive measurements of 24-h urinary sodium excretion) may amplify the effect of arterial pressure on target organ damage (ie, left ventricular mass and microalbuminuria) in a large group of normotensive subjects and patients with never-treated uncomplicated essential hypertension. Left ventricular mass (M-mode echocardiography) and urinary albumin excretion were assessed in 839 subjects (471 men and 368 women) aged 15 to 70 years, with elevated (60%) or normal arterial pressure. In the entire population, multivariate analysis indicated that the relationship between urinary sodium excretion and left ventricular mass index (β = 0.02, P < .01) as well as urinary albumin excretion (β = 0.001, P < .0001) was independent from sex, age, body mass index, and systolic arterial pressure. When subjects were divided into quintiles according to urinary sodium excretion, left ventricular mass index and urinary albumin excretion increased significantly from the lowest to the highest quintile in both genders, despite similar values of systolic arterial pressure. The slope of the regression line linking systolic arterial pressure to left ventricular mass index (in men) and urinary albumin excretion (in the entire population) obtained within each quintile of urinary sodium excretion, progressively and linearly increased from the lowest to the highest quintile. These results suggest that sodium intake may amplify the effect of arterial pressure on both the left ventricle and the kidney, and thus suggest that dietary sodium may be an independent factor of cardiovascular risk.