Prognostic utility of early systolic lengthening by speckle tracking in patients undergoing coronary artery bypass graft

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Independent Research Fund Denmark

Background

Early systolic lengthening (ESL), a paradoxical stretch of myocardial fibers, has been linked to myocardial viability and contractile dysfunction. We assessed the long-term prognostic potential of ESL in coronary artery bypass graft (CABG) patients.

Methods

We retrospectively included patients (n = 709; mean age 68 years; 85% men) who underwent speckle tracking echocardiography (median 15 days) prior to CABG. Endpoints were cardiovascular death (CVD) and all-cause mortality. We assessed amplitude of ESL (%), defined as peak positive strain, and duration of ESL (ms), determined as time from Q-wave on the ECG to peak positive strain. We applied Cox proportional hazards models adjusted for the clinical risk tool, EuroSCORE II.

Results

During median follow-up of 3.8 years [IQR 2.7 to 4.9 years], 45 (6%) experienced CVD and 80 (11%) died. In survival analyses adjusted for EuroSCORE II, amplitude of ESL was associated with CVD (HR 1.37 [95%CI 1.13 to 1.66], P = 0.001) and all-cause mortality (HR 1.31 [95%CI 1.13 to 1.54], P = 0.001). Similar findings applied to duration of ESL and CVD (HR 1.17 [95%CI 1.08 to 1.26], P < 0.001) and all-cause mortality (HR 1.14 [95%CI 1.07 to 1.21], P < 0.001). The prognostic value of ESL amplitude was modified by sex (P interaction < 0.05), such that it was greater in women for both endpoints (Figure 1A-B). When adding ESL duration to EuroSCORE II, the net reclassification index improved significantly for both CVD and all-cause mortality.

Conclusions

Assessment of ESL provides independent and incremental prognostic information in addition to the EuroSCORE II for CVD and all-cause mortality in CABG patients. The prognostic value was greater in women.

Abstract Figure. Prognostic value of ESL amplitude by sex

P4628A multiple biomarker approach for risk assessment after ST-segment elevation myocardial infarction

Background

Several biomarkers independently predict outcome following ST-segment elevation myocardial infarction (STEMI). We hypothesized that combining information from multiple circulating biomarkers with numerous pathophysiological pathways may improve biomarker risk stratification following a STEMI.

Method

This was a prospective study of 735 patients with STEMI treated with primary percutaneous coronary intervention. Seventeen biomarkers were drawn before revascularization, including adrenalin, noradrenalin, C-reactive protein (CRP), neutrophil gelatinase-associated lipocalin (NGAL), pro-atrial natriuretic peptide (pro-ANP), alfa-defensin, adiponectin, troponin I, hemoglobin, thrombocyte, and total leukocyte count. The primary outcome was a composite of cardiovascular death or heart failure (CVD/HF) identified by national registries. In the effort to identify the best model, the population was randomly split into two equally sized groups, a derivation cohort and a validation cohort. We used classification and regression tree (CART) analysis to develop a risk model. The identified risk model was hereafter applied to the whole cohort.

Results

Mean age was 63 years, 74% were male and 33% had hypertension. During a median follow-up time of 5.0 years (3.2; 5.0), we observed 185 primary events. After including all biomarkers in the initial model, the CART analysis created a risk model including pro-ANP, NGAL, and CRP (Figure 1a). The risk of CVD/HF increased incrementally with increasing risk group (Figure 1b). The risk remained significantly higher in groups 3 and 4 after multivariable adjustments (hazard ratio (HR)=3.38 [95% confidence interval (CI): 1.60; 7.16] p=0.001 and HR=6.55 [95% CI: 2.73; 15.76] p<0.001, respectively) when compared with group 1.

Figure 1

Conclusion

We developed a risk model based on multiple biomarkers (NGAL, CRP, and pro-ANP) determined from a CART analysis which may ease risk stratification after STEMI.

Acknowledgement/Funding

Sif Rasmussen received a scholarship grant from Herlev & Gentofte Hospital and the P. Carl Petersens Fond during preparation of this manuscript.

Evaluation of miLINC to shorten time to treatment for rifampicin-resistant Mycobacterium tuberculosis

BACKGROUND: Achieving the 90-90-90 targets for tuberculosis (TB) will require interventions that enhance diagnosis, linkage, treatment and adherence to care. As a first step in the process, our team designed a suite of smartphone applications known as miLINC to improve time from diagnosis to treatment initiation in drug-resistant TB patients.SETTING: Three clinical locations in a large, peri-urban district in KwaZulu-Natal, South Africa.OBJECTIVE: To assess the acceptability, feasibility and impact of the miLINC mobile health applications as a solution to reducing the time from presentation to treatment initiation of rifampicin-resistant (RR) TB patients.METHODS: We used a prospective, observational quality improvement evaluation of miLINC's impact among newly diagnosed patients with RR-TB.RESULTS: A convenience sample comprising details of 6341 patients with presumptive TB were entered into miLINC. Of the 631 TB-positive sputum specimens, 41 (6.5%) were found to be RR-TB. The mean time from clinical presentation to RR-TB treatment initiation was 3 days, 21 h, 17 min.CONCLUSION: This is the first study to suggest that the time from presentation to diagnosis and to treatment initiation for patients with RR-TB can be significantly improved using an integrated approach combining technology with appropriate human resources.

Benchmarking of aggregated length of stay after open and laparoscopic surgery for cancers of the digestive system

Background

Length of hospital stay (LOS) may serve as a surrogate measure of healthcare quality and resource use, particularly when transfers of care and readmissions are accounted for. This study aimed to benchmark true hospital stay by measuring index, transfer and readmission stays across the range of digestive cancer surgery.

Methods

A cohort study of all patients undergoing resection for cancer of the oesophagus, stomach, liver, pancreas, colon or rectum in 2012–2016 was undertaken. Index LOS, transfer and readmission stays were merged into an ‘aggregated’ length of stay (a‐LOS), and compared between organ sites and between open and minimal‐access approaches.

Results

In total, 24 354 resections were reported (mean age of patients 68·3 years; 51·3 per cent were men). Resections were reported as laparoscopic for 9151 procedures (37·6 per cent), with a further 283 (3·0 per cent) described as converted to open surgery. Use of a‐LOS compared with standard LOS added a median of 5 days for pancreatoduodenectomy, 4 days for major liver resections, 3 days for oesophageal and gastric resections, and 2 days for minor liver, distal pancreatic and rectal resections.

Conclusion

Overall hospital stay across organ sites and procedures is better described by a‐LOS. The study benchmarks the use of total hospital days during the first 30 days in a universal healthcare system.

Treatment of acute myocardial infarction in the sub-arctic region of Norway. Do we offer an equal quality of care?

Patients, relatives, healthcare workers and administrators are concerned about the quality of care offered. We aimed to explore the treatment of acute myocatrdial infarction (AMI) in Northern Norway, compare it with the national figures, and document whether there is an equal quality of care or not. The retrospective study included data on patients' treatment for AMI. The following sources were employed. The Norwegian Patient Registry, National Quality of Care Database, Norwegian Myocardial Infarction Registry and data from the National Air Ambulance Services of Norway. The period 2012-2014/15 was studied and the variables were: incidence of AMI, gender and age adjusted rates of AMI and revascularization (PCI, CABG) based on patient's place of living (according to hospital catchment area) and 30-day survival rate. The annual incidence of AMI was 9% higher in the northern region. Significant incidence variations (2.7–5.9 AMI/1000 inhabitants) between the hospitals' catchment areas were revealed. The 30-day survival rate varied between 85.1–92.1% between hospitals. The variation in revascularization/AMI rate was 0.72–1.54. Air amublance services' availability varied through the day. In conclusion, significant variations in the AMI rate and an unequal service within the region was revealed.

Successes, challenges and lessons from a novel deployment of Xpert(®) MTB/RIF at a major South African public event [Short Communication]

In a mobile deployment of Xpert(®) MTB/RIF (Xpert) at the public event for 2012 South African World TB Day, Xpert testing was offered to tuberculosis (TB) symptomatic clients from gold mining and surrounding communities. Considerations before implementation included effective TB symptom screening; safe, effective sputum collection; uninterrupted electricity supply; stringent instrument verification and provision of on-site results. Public event Xpert testing is feasible; however, the case-finding rate was very low (0.7%). We recommend exploring enhanced symptom screening algorithms to improve pre-test probability, cost-effectiveness analysis, exploring alternate electrical fail-safes and on-site data connectivity and improving management of client expectations.

Bone cement implantation syndrome in cemented hemiarthroplasty for femoral neck fracture: incidence, risk factors, and effect on outcome

BACKGROUND

Bone cement implantation syndrome (BCIS) is characterized by hypoxia, hypotension, and loss of consciousness occurring around the time of bone cementation. Using a recently proposed severity classification of BCIS, we estimated the incidence of and risk factors for BCIS and its impact on mortality in cemented hemiarthroplasty for femoral neck fractures.

METHODS

In this retrospective study, 1016 patients undergoing cemented hemiarthroplasty were included. Medical history and medication were obtained from medical records. Anaesthesia charts for all patients were reviewed for mean arterial pressure, arterial oxygen saturation, and heart rate before, during, and after cementation. Each patient was classified as having no BCIS (grade 0) or BCIS grade 1, 2, or 3, depending on the degree of hypotension, arterial desaturation, or loss of consciousness around cementation.

RESULTS

The incidence of BCIS grade 1, 2, and 3 were 21%, 5.1%, and 1.7%, respectively. Early mortality in BCIS grade 1 (9.3%) did not differ significantly from BCIS grade 0 (5.2%), while early mortality in BCIS grade 2 (35%) and grade 3 (88%) were significantly higher when compared with grades 0 and 1. Early mortality was also higher in BCIS grade 3 when compared with grade 2. Independent predictors for severe BCIS were: ASA grade III-IV, chronic obstructive pulmonary disease, and medication with diuretics or warfarin. Severe BCIS was associated with 16-fold increase in mortality.

CONCLUSIONS

BCIS is a commonly occurring phenomenon in cemented hemiarthroplasty and severe BCIS has a huge impact on early and late mortality.

High field structural MRI reveals specific episodic memory correlates in the subfields of the hippocampus

The involvement of the hippocampus (HC) in episodic memory is well accepted; however it is unclear how each subfield within the HC contributes to memory function. Recent magnetic resonance imaging (MRI) studies suggest differential involvement of hippocampal subfields and subregions in episodic memory. However, most structural MRI studies have examined the HC subfields within a single subregion of the HC and used specialised experimental memory paradigms. The purpose of the present study was to determine the association between volumes of HC subfields throughout the entire HC structure and performance on standard neuropsychological memory tests in a young, healthy population. We recruited 34 healthy participants under the age of 50. MRI data was acquired with a fast spin echo (FSE) sequence yielding a 0.52×0.68×1.0 mm(3) native resolution. The HC subfields - the cornu ammonis 1-3 (CA), dentate gyrus (DG), and subiculum (SUB) - were segmented manually within three hippocampal subregions using a previously defined protocol. Participants were administered the Wechsler Memory Scale, 4th edition (WMS-IV) to assess performance in episodic memory using verbal (Logical Memory, LM) and visual (Designs, DE; visual-spatial memory, DE-Spatial; visual-content memory, DE-Content) memory subtests. Working memory subtests (Spatial Addition, SA; and Symbol Span, SSP) were included as well. Working memory was not associated with any HC volumes. Volumes of the DG were correlated with verbal memory (LM) and visual-spatial memory (DE-Spatial). Posterior CA volumes correlated with both visual-spatial and visual-object memory (DE-Spatial, DE-Content). In general, anterior subregion volumes (HC head) correlated with verbal memory, while some anterior and many posterior HC subregion volumes (body and tail) correlated with visual memory scores (DE-Spatial, DE-Content). In addition, while verbal memory showed left-lateralized associations with HC volumes, visual memory was associated with HC volumes bilaterally. This the first study to examine the associations between hippocampal subfield volumes across the entire hippocampal formation with performance in a set of standard memory tasks.

The effect of thoracentesis on lung function and transthoracic electrical bioimpedance

This study aimed to determine the relationship between improvement in lung function and changes in transthoracic electrical bioimpedance (TEB) after thoracentesis in patients with pleural effusions. Fifteen patients with pleural effusions due to either malignant (n = 8) or cardiac (n = 7) diseases were included. Pulmonary function was assessed before and after thoracentesis. During thoracentesis the patients were monitored with TEB. Using linear correlation analysis, the increases for each litre of aspirated thoracic fluid were: forced expiratory volume in 1 s (FEV1) 0.261; forced vital capacity (FVC) 0.331; total lung capacity (TLC) 0.58; and the lung diffusing capacity (DLCO); 2.4 ml min-1 mmHg-1. Baseline impedance increased by 2.3 Ohm l-1 aspirated thoracic fluid. The relative increase in baseline impedance was twice as high for patients with cancer as for patients with heart failure (P < 0.05). We found only minor changes in systolic blood pressure and mean arterial pressure. The improvements in diffusing capacity, airflow, and lung volumes after thoracentesis are correlated to an increase in baseline impedance, but changes are dependent on the primary disease.

[Impedance cardiography--non-invasive measurement of central hemodynamic data]

The theory, method and apparatus behind a new computer technology for transthoracic electrical bioimpedance are described. Measurements and calculations of changes in the electrical conductivity of the thoracic segment during systolic upstroke provides the basis for non-invasive determination of stroke volume and cardiac output. Bioimpedance further offers a sensitive indicator of the content of thoracic fluid. Reports comparing measurements of cardiac output in various clinical conditions by bioimpedance versus invasive methods in general show good correlation. The field of applications and limitations of bioimpedance are described. Measurements are reproducible and the method can also be used in evaluating the cardiodynamic exercise response.

Hypersensitivity of delayed type in hypertensive patients

The agarose migration technique was used for demonstration of delayed-type hypersensitivity to arterial vessel wall antigens in patients suffering from chronic essential hypertension. By means of this technique, it was demonstrated that the migration indices from the hypertensive patients differed significantly from the normotensive control persons, P less than 0.005. The significant difference was abolished when anti-LIF was added to the migration tests. This means that a hypersensitivity of the delayed type had developed in the hypertensive patients and the results indicated that the hypersensitivity was an autoimmunity to arterial vessel wall antigens.

Autoactivation of human recombinant coagulation factor VII

Single-chain human recombinant factor VII produced by transfected baby hamster kidney cells was purified to homogeneity in the presence of benzamidine. The amidolytic activity of single-chain recombinant factor VII with a peptidylnitroanilide substrate, methoxycarbonyl-D-cyclohexanylglycyl-L-arginine-p-nitroanilide, was less than 1% of that obtained with factor VIIa. Purified single-chain recombinant factor VII spontaneously activated in the absence of inhibitor. The activation reaction was enhanced by at least 2 orders of magnitude in the presence of a positively charged surface, provided either as an anion-exchange matrix or as poly(D-lysine). The progress curve for factor VIIa generation was sigmoidal. Benzamidine inhibits recombinant factor VIIa activity and factor VII activation with identical inhibition constants (Ki) of 11 mM. In contrast, benzamidine inhibition of bovine factor Xa and bovine factor IIa was observed at Ki values equal to 0.3 and 0.5 mM, respectively. Bovine factors Xa and IIa are known activators of factor VII and the most likely contaminants of our recombinant factor VII preparations. Single-chain recombinant factor VII purified from cells cultured in the absence of bovine serum activated at the same rate as factor VII from cells cultured in the presence of bovine serum. This also excluded the possibility that the activation reaction was caused by contaminating bovine proteases. On the basis of these observations, we propose that factor VII is autoactivated in vitro in the presence of a positively charged surface.

Aluminum concentrations in serum, dialysate, urine and bone among patients undergoing continuous ambulatory peritoneal dialysis (CAPD)

Aluminum (Al) concentration in serum, urine, and dialysate was estimated in 21 patients undergoing continuous ambulatory peritoneal dialysis (CAPD). In 12 of the patients bone Al concentration was measured as well. Mean serum Al level was 32.4 +/- 21.0 micrograms/l. The Al concentrations in the dialysate and urine were 9.1 +/- 4.1 micrograms/l and 52.5 +/- 47.3 micrograms/l, respectively. Bone Al concentration was 21.0 +/- 14.9 ppm and correlated significantly with concentrations of Al in serum (p less than 0.01) and dialysate (p less than 0.01). A mass transfer (MT) from the patients to the dialysate was observed in all patients (-44.0 +/- 28.8 micrograms/24 h). There was a highly significant correlation between peritoneal Al MT and serum Al (p less than 0.001), actual Al consumption (p less than 0.05) and bone Al concentration (p less than 0.005) supporting the existence of an overflow phenomenon. Despite very low Al levels in the dialysate, patients are at risk of elevated Al levels in the serum, dialysate, urine and bone because of consumption of Al-containing phosphate binders.

Duration of delayed-type autoimmunity against arterial vessel-wall antigens following acute hypertensive damage to arterial vessels in rats

Acute hypertensive damage to small arteries and arterioles in rats was induced by intravenous injections of Hypertensin. The in vitro immunological method of the agarose migration technique was used to demonstrate delayed-type autoimmunity against arterial vessel-wall antigens. By this technique the autoimmunity could be demonstrated for about 16 weeks after the acute hypertensive damage to the arterial vessels. The results of the autoimmunity were given as migration indices. These were lowest during the first 4-5 weeks after the damage to the vessels whereupon they showed higher and higher values, and finally the migration indices were identical with those of the control rats after about 16 weeks.

Further evidence of the development of delayed-type autoimmunity against arterial vessel-wall antigens following acute hypertensive damage to arterial vessels in rats

Acute hypertensive damage to arterial vessels was induced by intravenous injections of hypertension. The in vitro immunological method of the agarose migration technique was used for demonstration of delayed-type autoimmunity against arterial vessel-wall antigens following the damage of the arterial vessels. By means of this technique it was demonstrated that the migration indices from the rats with induced hypertension differed significantly from the control rats, P less than 0.005. This means that an autoimmunity of the delayed type had developed after the hypertensive damage to the arterial vessels. The autoimmunity was tissue specific.

Induction of chronic arterial hypertension in rats by repeated transient hypertensive rises in blood pressure. Possible pathogenetic role of delayed hypersensitivity against arteries and arterioles

Repeated transient rises in blood pressure to hypertensive levels were induced by intravenous injections of angiotensin once or twice weekly. This procedure induced chronic arterial hypertension in five of fourteen rats (36%) within 4-6 weeks of starting the injections. Intracutaneous tests using homogenized common carotid arteries and histological examination of the kidneys gave support to the hypothesis that the transient rises in blood pressure to hypertensive levels resulted in a delayed hypersensitivity (DHS) reaction against components in small arteries and arterioles. This DHS reaction seemed to be responsible for an increased permeability of arterial vessels to plasma components causing exudative thickening of the walls of small arteries and arterioles and thereby narrowing of their lumina. When the lumina of small arteries and arterioles are narrowed, peripheral resistance to blood flow increases, and arterial hypertension results.

Transfer of arterial hypertension by splenic cells from DOCA-salt hypertensive and renal hypertensive rats to normotensive recipients

Arterial hypertension was transferred from DOCA-salt hypertensive and renal hypertensive rats to normotensive rats by intravenous injection of splenic cells. Thirteen normotensive recipients were injected intravenously with splenic cells from the hypertensive donors. Eleven developed arterial hypertension (85%), that is, with a systolic blood pressure exceeding 140 mm Hg. Three of the recipients developed hypertensive levels up to 155-160 mm Hg, which was almost up to the levels in the donors. The increase of the blood pressure in the recipients was significant when compared to controls injected intravenously with splenic cells from normotensive donors (p less than 0.001). Skin tests, performed by intracutaneous injection of homogenized common carotid arteries in half of the recipients, showed positive reactions 24 hours after the injection. Microscopical examination of heart and kidney from the other half demonstrated mononuclear infiltration into arterial and arteriolar walls and exudative changes in these walls. Due to exudative thickening of the vessel walls the lumina were narrowed. The hypothesis is advanced that the recipient rats developed arterial hypertension as a result of a transferred delayed hypersensitivity directed against the arterial walls. This hypersensitivity reaction caused insudation of plasma components into the arterial walls, narrowing of their lumina and an increased peripheral resistance to the blood flow, so that arterial hypertension developed.

Acute hypertensive damage of arterial vessels of the heart

Experimentally-induced acute angiotensin hypertension has been shown to increase the permeability of cardial arteries and arterioles to plasma components within a few hours. Only in one of the coronary arteries was an increased and focal permeability for plasma components demonstrated, the penetration taking place into the entire thickness of the vessel wall. However, the permeability observed in intramyocardial small arteries and arterioles showed a distinct deposition of plasma components, both in the tunica intima and the tunica media and usually in the entire circumference of the vessels. The results support the view that an increased arterial permeability of the myocardial vessels for plasma components is an important initial stage in the development of hypertensive vascular disease of the heart.

Increased permeability for plasma components of the cerebral vessels during acute angiotensin hypertension in rats

Experimentally induced acute angiotensin hypertension has been shown to increase the permeability of cerebral arterioles, venules and veins to plasma components whthin a few hours. This increase in permiability was demonstrated by means of circulating homologous fluorescent serum proteins and colloidal carbon particles. The results support the view that an increased permeability of the cerebral vessels to plasma components is either a causal or an additional pathogenetic factor in the development of the hypertensive encephalopathy.

Delayed hypersensitivity and borderline essential hypertension

By means of the leucocyte migration technique, it has been demonstrated that the migration indices from 19 patients suffering from borderline essential hypertension are significantly different from those of 19 normal persons. These results support the view that delayed hypersensitivity directed against arterial wall components is a possible pathogenetic factor in patients suffering from essential hypertension.

Penetration of fluorescent homologous serum proteins into the wall of the aorta in rats with acute angiotensin hypertension

A few hours of acute angiotensin hypertension in rats increased the permeability of the thoracic part of the aorta for plasma components. The permeability, which was demonstrated by means of homologous circulating fluorescent serum proteins, seemed to be diffuse rather than focal. The fluorescent proteins penetrated into the whole thickness of the aortic wall, but were to a great extent deposited in the subendothelial space and the most luminal part of the tunica media. The deposition took place in the greater part of the circumference of the aortic wall. These results are in agreement with the insudative theory of atherogenesis, and the initial stage seems to be a "damming back" of some of the serum or plasma proteins for deposition in the subendothelial space and the most luminal part of the tunica media.