Combined Arterial Hypertension and Ischemic Stroke Exaggerate Anesthesia-Related Hypotension and Cerebral Oxygenation Deficits: A Preclinical Study

BACKGROUND

Intraoperative arterial hypotension (IOH) is a common side effect of general anesthesia (GA), associated with poor outcomes in ischemic stroke. While IOH is more prevalent with hypertension, it is unknown whether IOH may differ when GA is induced during ischemic stroke, versus other clinical settings. This is important given that many stroke patients receive GA for endovascular thrombectomy.

METHODS

We evaluate the cardiovascular responses to volatile GA (isoflurane in 100% o2 ) before and during middle cerebral artery occlusion stroke in rats instrumented to record blood pressure (BP) and cerebral tissue oxygenation (p o2 ) in the projected penumbra, in clinically relevant cohorts of normotensive (Wistar rat, n = 10), treated hypertensive (spontaneously hypertensive [SH] + enalapril, n = 12), and untreated hypertensive (SH rat, n = 12).

RESULTS

During baseline induction of GA, IOH was similar in normotensive, treated hypertensive, and untreated hypertensive rats during the induction phase (first 10 minutes) (-24 ± 15 vs -28 ± 22 vs -48 ± 24 mm Hg; P > .05) and across the procedure (-24 ± 13 vs -30 ± 35 vs -39 ± 27 mm Hg; P > .05). Despite the BP reduction, cerebral p o2 increased by ~50% in all groups during the procedure. When inducing GA after 2 hours, all stroke groups showed a greater magnitude IOH compared to baseline GA induction, with larger falls in treated (-79 ± 24 mm Hg; P = .0202) and untreated(-105 ± 43 mm Hg; P < .001) hypertensive rats versus normotensives (-49 ± 21 mm Hg). This was accompanied by smaller increases in cerebral p o2 in normotensive rats (19% ± 32%; P = .0144 versus no-stroke); but a decrease in cerebral p o2 in treated (-11% ± 19%; P = .0048) and untreated (-12% ± 15%; P = .0003) hypertensive rats. Sham animals (normotensive and hypertensive) showed similar magnitude and pattern of IOH when induced with GA before and after sham procedure.

CONCLUSIONS

Our findings are the first demonstration that ischemic stroke per se increases the severity of IOH, particularly when combined with a prior history of hypertension; this combination appears to compromise penumbral perfusion.

Carotid body: an emerging target for cardiometabolic co-morbidities

NEW FINDINGS

What is the topic of this review? Regarding the global metabolic syndrome crisis, this review focuses on common mechanisms for high blood sugar and high blood pressure. Connections are made between the homeostatic regulation of blood pressure and blood sugar and their dysregulation to reveal signalling mechanisms converging on the carotid body. What advances does it highlight? The carotid body plays a major part in the generation of excessive sympathetic activity in diabetes and also underpins diabetic hypertension. As treatment of diabetic hypertension is notoriously difficult, we propose that novel receptors within the carotid body may provide a novel treatment strategy.

ABSTRACT

The maintenance of glucose homeostasis is obligatory for health and survival. It relies on peripheral glucose sensing and signalling between the brain and peripheral organs via hormonal and neural responses that restore euglycaemia. Failure of these mechanisms causes hyperglycaemia or diabetes. Current anti-diabetic medications control blood glucose but many patients remain with hyperglycemic condition. Diabetes is often associated with hypertension; the latter is more difficult to control in hyperglycaemic conditions. We ask whether a better understanding of the regulatory mechanisms of glucose control could improve treatment of both diabetes and hypertension when they co-exist. With the involvement of the carotid body (CB) in glucose sensing, metabolic regulation and control of sympathetic nerve activity, we consider the CB as a potential treatment target for both diabetes and hypertension. We provide an update on the role of the CB in glucose sensing and glucose homeostasis. Physiologically, hypoglycaemia stimulates the release of hormones such as glucagon and adrenaline, which mobilize or synthesize glucose; however, these counter-regulatory responses were markedly attenuated after denervation of the CBs in animals. Also, CB denervation prevents and reverses insulin resistance and glucose intolerance. We discuss the CB as a metabolic regulator (not just a sensor of blood gases) and consider recent evidence of novel 'metabolic' receptors within the CB and putative signalling peptides that may control glucose homeostasis via modulation of the sympathetic nervous system. The evidence presented may inform future clinical strategies in the treatment of patients with both diabetes and hypertension, which may include the CB.

GLP1R Attenuates Sympathetic Response to High Glucose via Carotid Body Inhibition

Supplemental Digital Content is available in the text.

Aberrant sympathetic nerve activity exacerbates cardiovascular risk in hypertension and diabetes, which are common comorbidities, yet clinically sympathetic nerve activity remains poorly controlled. The hypertensive diabetic state is associated with increased reflex sensitivity and tonic drive from the peripheral chemoreceptors, the cause of which is unknown. We have previously shown hypertension to be critically dependent on the carotid body (CB) input in spontaneously hypertensive rat, a model that also exhibits a number of diabetic traits. CB overstimulation by insulin and leptin has been similarly implicated in the development of increased sympathetic nerve activity in metabolic syndrome and obesity. Thus, we hypothesized that in hypertensive diabetic state (spontaneously hypertensive rat), the CB is sensitized by altered metabolic signaling causing excessive sympathetic activity levels and dysfunctional reflex regulation.

Identifying the prevalence of undiagnosed cardiovascular disease risk factors in healthy Indians

Funding Acknowledgements

Type of funding sources: None.

Introduction

 

Cardiovascular disease (CVD) including heart disease and stroke, is the leading cause of death globally and in India. 

The importance of primary prevention, defined as interventions designed to modify adverse risk factors with the goal of preventing an initial CVD event has been established beyond doubt by several population based studies in healthy individuals.

While there have been many studies defining the high prevalence in CVD risk factors in Indian population, this study sought to determine the prevalence of undiagnosed modifiable CVD risk factors in healthy individuals. 

Methods

The  cross sectional, analytical study was carried out at the hospitals, from 1st April 2015 to 31st dec 2017. Subjects between 18 - 70 years of age who were healthy and were undergoing health checkup were included in the study. A total of 5000 patients were screened, those having existing CVD risk factors were excluded from the study. 

This study was approved by the institutional ethics committee of the hospital. Written informed consent was obtained from all subjects. The data collection record sheet was prepared based on validated and standardized questionnaires which was used to enter all data. 

Physical examination for vitals and BMI was done by qualified physicians. Blood investigations were done for diabetes and dyslipidemia and thyroid dysfunction. ACC/AHA criteria was used for diagnosis of  hypertension, ADA criteria for diabetes. Joint British society 3 risk score and ASCVD risk score was calculated using standard calculators.

Results

At screening, 4998 participants aged ≥18 years were approached to participate in study. The study population included 2705 men (68.1%) and 1265 women (31.9%) with a mean age of 68± 18.8 years. The most prevalent risk factor was overweight and obesity (71.2%).

The prevalence of undiagnosed HTN was 73.3%, undiagnosed pre-diabetes was 24.9% and undiagnosed diabetes was 28.3%. Out of total, 44.3% subjects had high level of low-density lipoprotein and 36.6% subjects had low level of high-density lipoprotein, 20.1% subjects had high level of very-low density lipoprotein (VLDL) and 17.3% subjects had high level of triglyceride.

Tobacco smoking was present in 7.7% of the population. The risk estimation predicted 29.1% of the study participants to have more than 10% risk of heart attack/stroke risk at 10 years.

Conclusion

Our study reveals a fairly good snapshot of CVDs risk factors in healthy general population. Increased prevalence of high BMI, undiagnosed HTN, diabetes, dyslipidemia was present in our study population. 

The population had significantly high predicted risk of heart attack/stroke. These findings warrant the need of community based life style modifications, regular health checkup for healthy population for early detection and modification of CVD risk factors.

Can We Avoid Axillary Lymph Node Dissection (ALND) in Patients with 1-2 Positive Sentinel/Low Axillary Lymph Nodes (SLN/LAS+) in the Indian Setting?

The ACOSOG Z0011 study, heralded as a "practice changing" trial, suggested that women with T1-2 breast cancer with 1-2 SLN+, undergoing breast conservation therapy, need not be offered further ALND. However, whether these results are applicable to all women in the Indian setting, it remains debatable. A retrospective audit of all cN0 operated from 2013 to 2018 was conducted. We analyzed the percentage of additional LN positive (LN+) in the ALND group and compared it to the ACOZOG Z11 trial. Of the 2350 cN0 with EBC who underwent LAS, 687 (29%) had positive lymph nodes on final histopathology. Five hundred ninety-seven (86.9%) patients had 1-2 LN+, 40 (5.8%) patients had 3 LN+, and 50 (7.3%) had 4 or more nodes positive. Demographic features in the ACOSOG Z11 are different from those in our study, looking at ACOZOG Z11 versus our cohort-median pT 1.7 cm versus 3 cm, 45% micrometastasis versus 99.16% macrometastasis, and 28-30% grade 3 tumors versus 73.7%. In our cohort 31.82% of the 1-2 LN positive had additional LN+ on ALND. Keeping in mind the difference in clinicopathological features between our cohort and that of ACOZOG Z0011 and that 31.82% of women had additional LN+ on ALND, it may not be appropriate to apply the results of the ACOSOG Z0011 trial directly to our general population. Possibly, only a select subset of patients who match the trial population of the ACOSOG Z11 could be offered observation of the axilla and validated nomograms can be used to identify high-risk patients.

Comparison of accelerometer-derived physical activity levels between individuals with and without cancer: a UK Biobank study

Aim: To identify the difference in physical activity (PA) levels between individuals with and without cancer, and to estimate all-cause mortality associated with this difference. Methods: Current cancer, cancer survivor and cancer-free groups were identified from the UK Biobank. We used multivariate and Cox regression to estimate PA differences and association of PA with all-cause mortality. Results: Compared with the cancer-free individuals, participants in the two cancer groups had fewer minutes in moderate-to-vigorous PA per day in adjusted analyses. The PA difference was associated with higher mortality in the current cancer group. Conclusion: Patients with a history of cancer were less active than those without cancer, and PA is associated with increased mortality. PA improvement strategies in cancer patients must be explored.

Hypertensive Response to Ischemic Stroke in the Normotensive Wistar Rat

Background and Purpose—

Over 80% of ischemic stroke patients show an abrupt increase in arterial blood pressure in the hours and days following ischemic stroke. Whether this poststroke hypertension is beneficial or harmful remains controversial and the underlying physiological basis is unclear.

Methods—

To investigate the dynamic cardiovascular response to stroke, adult Wistar rats (n=5–8 per group, 393±34 g) were instrumented with telemeters to blood pressure, intracranial pressure, renal sympathetic nerve activity, and brain tissue oxygen in the predicted penumbra (P o 2 ). After 2 weeks of recovery, cardiovascular signals were recorded for a 3-day baseline period, then ischemic stroke was induced via transient middle cerebral artery occlusion, or sham surgery. Cardiovascular signals were then recorded for a further 10 days, and the functional sensorimotor recovery assessed using the cylinder and sticky dot tests.

Results—

Baseline values of all variables were similar between groups. Compared to sham, in the 2 days following stroke middle cerebral artery occlusion produced an immediate, transient rise above baseline in mean blood pressure (21±3 versus 2±4 mm Hg; P <0.001), renal sympathetic nerve activity (54±11% versus 7±4%; P =0.006), and cerebral perfusion pressure (12±5 versus 1±4; P ≤0.001). Intracranial pressure increased more slowly, peaking 3 days after middle cerebral artery occlusion (14±6 versus −1±1 mm Hg; P <0.001). Treating with the antihypertensive agent nifedipine after stroke (1.5–0.75 mg/kg per hour SC) ameliorated poststroke hypertension (12±3 mm Hg on day 1; P =0.041), abolished the intracranial pressure increase (3±1; P <0.001) and reduced cerebral perfusion pressure (10±3 mm Hg; P =0.017). Preventing poststroke hypertension affected neither the recovery of sensorimotor function nor infarct size.

Conclusions—

These findings suggest that poststroke hypertension is immediate, temporally matched to an increase in sympathetic outflow, and elevates cerebral perfusion pressure for several days after stroke, which may enhance cerebral perfusion. Preventing poststroke hypertension does not appear to worsen prognosis after stroke in young, normotensive, and otherwise healthy rats.

Visual Overview—

An online visual overview is available for this article.

To evaluate and compare the efficacy of combined sucrose and non-nutritive sucking for analgesia in newborns undergoing minor painful procedure: a randomized controlled trial

OBJECTIVE

The objective of this study was to evaluate and compare the efficacy of combined sucrose and non-nutritive sucking (NNS) for analgesia in newborn infants undergoing heel-stick procedures.

STUDY DESIGN

This randomized control trial was conducted in the neonatal intensive care unit of a tertiary care hospital over a period of 1 year. One hundred and eighty full-term neonates with birth weight >2200 g and age >24 h were randomized to one of four interventions administered 2 min before the procedure: 2 ml of 30% sucrose (group I, n=45) or NNS (group II, n=45) or both (group III, n=45) or none (group IV, n=45). Primary outcome was composite score based on Premature Infant Pain Profile (PIPP) score.

RESULT

Baseline variables were comparable among the groups. Median (interquartile range) PIPP score was 3 (2 to 4) in group III as compared with 7 (6.5 to 8) in group I, 9 (7 to 11) in group II and 13 (10.5 to 15) in group IV. Group III had significant decrease in the median PIPP score compared with other groups (P=0.000). Median PIPP score also decreased significantly with any intervention as compared with no intervention (P=0.000).

CONCLUSION

Sucrose and/or NNS are effective in providing analgesia in full-term neonates undergoing heel-stick procedures, with the combined intervention being more effective compared with any single intervention.

Efficacy and safety over 26 weeks of an oral treatment strategy including sitagliptin compared with an injectable treatment strategy with liraglutide in patients with type 2 diabetes mellitus inadequately controlled on metformin: a randomised clinical trial

AIMS/HYPOTHESIS

The aim of this work was to compare treatment intensification strategies based on orally administered vs injectable incretin-based antihyperglycaemic agents in patients with type 2 diabetes mellitus on metformin monotherapy.

METHODS

In a 26 week, open-label study, 653 patients (baseline HbA1c = 8.2% [66 mmol/mol]) were randomised at 111 sites in 21 countries in a 1:1 ratio to a strategy using oral agents (starting with sitagliptin 100 mg/day) or a strategy using the injectable drug liraglutide starting at a dose of 0.6 mg/day, up-titrated to 1.2 mg/day after 1 week. The following patients with type 2 diabetes mellitus were recruited for the study: those aged 18-79 years, on a stable dose of metformin monotherapy ≥1,500 mg/day for ≥12 weeks, with an HbA1c ≥7.0% (53 mmol/mol) and ≤11.0% (97 mmol/mol) and a fasting fingerstick glucose (FFG) <15 mmol/l (<270 mg/dl) at the randomisation visit, deemed capable by the investigator of using a Victoza pen injection device (containing 6 mg/ml liraglutide; Novo Nordisk, Bagsværd, Denmark). Women taking part in the study agreed to remain abstinent or use an acceptable method of birth control during the study. Randomisation was performed via a computer-generated allocation schedule using an interactive voice response system. After 12 weeks, patients on sitagliptin with HbA1c  ≥ 7.0% (53 mmol/mol) and fasting glucose >6.1 mmol/l had their treatment intensified with glimepiride; patients on liraglutide with HbA1c  ≥ 7.0% (53 mmol/mol) had the dose up-titrated to 1.8 mg/day. The primary analysis assessed whether the strategy using oral drugs was non-inferior to that using an injectable drug regarding HbA1c change from baseline at week 26 using a per-protocol (PP) population and a non-inferiority margin of 0.4%.

RESULTS

In the PP population (522 patients included: oral strategy, n = 269; injectable strategy, n = 253) antihyperglycaemic therapy was intensified at week 12 in 50.2% and 28.5%, respectively. HbA1c decreased over 26 weeks in both treatment strategy groups, with a larger initial reduction at week 12 in the injectable strategy group. The LS mean change in HbA1c at week 26 was -1.3% (95% CI -1.4, -1.2) in the oral strategy group and -1.4% (95% CI -1.5, -1.3) in the injectable strategy group; the study met the non-inferiority criterion. Both treatment regimens were generally well tolerated; hypoglycaemia was reported more often with the oral strategy, while nausea, vomiting, diarrhoea and abdominal pain were reported more often with the injectable strategy.

CONCLUSIONS/INTERPRETATION

An oral, incretin-based treatment strategy with sitagliptin and, if needed, glimepiride may be a good approach in many patients with type 2 diabetes mellitus for managing inadequate glycaemic control on metformin monotherapy, as compared with an injectable treatment strategy with liraglutide. The oral and injectable strategies had similar effects on HbA1c and had good overall tolerability. Trial registration ClinicalTrials.gov NCT01296412 Funding The study was sponsored by Merck Sharp & Dohme Corp., a subsidiary of Merck and Co., Inc., Whitehouse Station, NJ, USA.

Drug susceptibility testing of Mycobacterium tuberculosis against second-line drugs using the Bactec MGIT 960 System

OBJECTIVE

To establish the critical test concentrations for seven second-line anti-tuberculosis drugs in the Bactec Mycobacterial Growth Indicator Tube (MGIT) 960 TB system and to evaluate its efficacy compared to the Bactec 460 TB system.

DESIGN

This study was carried out in three phases. In Phase I, pan-susceptible strains were tested to establish the minimum inhibitory concentration; in Phase II, mostly resistant strains were tested to determine a critical test concentration; and in Phase III, actual clinical isolates were tested to validate the optimal critical concentrations established in Phases I and II.

RESULTS

The critical concentrations established for seven second-line drugs with the Bactec MGIT 960 system are amikacin 1.0 microg/ml, capreomycin 2.5 microg/ml, kanamycin 2.5 microg/ml, ofloxacin 2.0 microg/ml, moxifloxacin 1.0 microg/ml, ethionamide 5.0 microg/ml and para-amino salicylic acid 4.0 microg/ml.

CONCLUSION

The Bactec MGIT 960 System is an accurate and reliable method for rapid drug susceptibility testing (DST) of Mycobacterium tuberculosis against second-line drugs. In the present study, few of the strains were resistant to fluoroquinolones and further DST for this group is required.