Coronary sinus reducer for the treatment of refractory angina (ORBITA-COSMIC): a randomised, placebo-controlled trial

BACKGROUND

The coronary sinus reducer (CSR) is proposed to reduce angina in patients with stable coronary artery disease by improving myocardial perfusion. We aimed to measure its efficacy, compared with placebo, on myocardial ischaemia reduction and symptom improvement.

METHODS

ORBITA-COSMIC was a double-blind, randomised, placebo-controlled trial conducted at six UK hospitals. Patients aged 18 years or older with angina, stable coronary artery disease, ischaemia, and no further options for treatment were eligible. All patients completed a quantitative adenosine-stress perfusion cardiac magnetic resonance scan, symptom and quality-of-life questionnaires, and a treadmill exercise test before entering a 2-week symptom assessment phase, in which patients reported their angina symptoms using a smartphone application (ORBITA-app). Patients were randomly assigned (1:1) to receive either CSR or placebo. Both participants and investigators were masked to study assignment. After the CSR implantation or placebo procedure, patients entered a 6-month blinded follow-up phase in which they reported their daily symptoms in the ORBITA-app. At 6 months, all assessments were repeated. The primary outcome was myocardial blood flow in segments designated ischaemic at enrolment during the adenosine-stress perfusion cardiac magnetic resonance scan. The primary symptom outcome was the number of daily angina episodes. Analysis was done by intention-to-treat and followed Bayesian methodology. The study is registered with ClinicalTrials.gov, NCT04892537, and completed.

FINDINGS

Between May 26, 2021, and June 28, 2023, 61 patients were enrolled, of whom 51 (44 [86%] male; seven [14%] female) were randomly assigned to either the CSR group (n=25) or the placebo group (n=26). Of these, 50 patients were included in the intention-to-treat analysis (24 in the CSR group and 26 in the placebo group). 454 (57%) of 800 imaged cardiac segments were ischaemic at enrolment, with a median stress myocardial blood flow of 1·08 mL/min per g (IQR 0·77-1·41). Myocardial blood flow in ischaemic segments did not improve with CSR compared with placebo (difference 0·06 mL/min per g [95% CrI -0·09 to 0·20]; Pr(Benefit)=78·8%). The number of daily angina episodes was reduced with CSR compared with placebo (OR 1·40 [95% CrI 1·08 to 1·83]; Pr(Benefit)=99·4%). There were two CSR embolisation events in the CSR group, and no acute coronary syndrome events or deaths in either group.

INTERPRETATION

ORBITA-COSMIC found no evidence that the CSR improved transmural myocardial perfusion, but the CSR did improve angina compared with placebo. These findings provide evidence for the use of CSR as a further antianginal option for patients with stable coronary artery disease.

FUNDING

Medical Research Council, Imperial College Healthcare Charity, National Institute for Health and Care Research Imperial Biomedical Research Centre, St Mary's Coronary Flow Trust, British Heart Foundation.

A double-blind, randomised, placebo-controlled trial of the coronary sinus Reducer in refractory angina: design and rationale of the ORBITA-COSMIC trial

The coronary sinus Reducer (CSR) is an hourglass-shaped device which creates an artificial stenosis in the coronary sinus. Whilst placebo-controlled data show an improvement in angina, these results are unreplicated and are the subject of further confirmatory research. The mechanism of action of this unintuitive therapy is unknown. The Coronary Sinus Reducer Objective Impact on Symptoms, MRI Ischaemia, and Microvascular Resistance (ORBITA-COSMIC) trial is a randomised, placebo-controlled, double-blind trial investigating the efficacy of the CSR. Patients with (i) established epicardial coronary artery disease, (ii) angina on maximally tolerated antianginal medication, (iii) evidence of myocardial ischaemia and (iv) no further options for percutaneous coronary intervention or coronary artery bypass grafting will be enrolled. Upon enrolment, angina and quality-of-life questionnaires, treadmill exercise testing and quantitative stress perfusion cardiac magnetic resonance (CMR) imaging will be performed. Participants will record their symptoms daily on a smartphone application throughout the trial. After a 2-week symptom assessment phase, participants will be randomised in the cardiac catheterisation laboratory to CSR or a placebo procedure. After 6 months of blinded follow-up, all prerandomisation tests will be repeated. A prespecified subgroup will undergo invasive coronary physiology assessment at prerandomisation and follow-up. The primary outcome is stress myocardial blood flow on CMR. Secondary outcomes include angina frequency, quality of life and treadmill exercise time. (ClinicalTrials.gov: NCT04892537).

A Placebo-Controlled Trial of Percutaneous Coronary Intervention for Stable Angina

BACKGROUND

Percutaneous coronary intervention (PCI) is frequently performed to reduce the symptoms of stable angina. Whether PCI relieves angina more than a placebo procedure in patients who are not receiving antianginal medication remains unknown.

METHODS

We conducted a double-blind, randomized, placebo-controlled trial of PCI in patients with stable angina. Patients stopped all antianginal medications and underwent a 2-week symptom assessment phase before randomization. Patients were then randomly assigned in a 1:1 ratio to undergo PCI or a placebo procedure and were followed for 12 weeks. The primary end point was the angina symptom score, which was calculated daily on the basis of the number of angina episodes that occurred on a given day, the number of antianginal medications prescribed on that day, and clinical events, including the occurrence of unblinding owing to unacceptable angina or acute coronary syndrome or death. Scores range from 0 to 79, with higher scores indicating worse health status with respect to angina.

RESULTS

A total of 301 patients underwent randomization: 151 to the PCI group and 150 to the placebo group. The mean (±SD) age was 64±9 years, and 79% were men. Ischemia was present in one cardiac territory in 242 patients (80%), in two territories in 52 patients (17%), and in three territories in 7 patients (2%). In the target vessels, the median fractional flow reserve was 0.63 (interquartile range, 0.49 to 0.75), and the median instantaneous wave-free ratio was 0.78 (interquartile range, 0.55 to 0.87). At the 12-week follow-up, the mean angina symptom score was 2.9 in the PCI group and 5.6 in the placebo group (odds ratio, 2.21; 95% confidence interval, 1.41 to 3.47; P<0.001). One patient in the placebo group had unacceptable angina leading to unblinding. Acute coronary syndromes occurred in 4 patients in the PCI group and in 6 patients in the placebo group.

CONCLUSIONS

Among patients with stable angina who were receiving little or no antianginal medication and had objective evidence of ischemia, PCI resulted in a lower angina symptom score than a placebo procedure, indicating a better health status with respect to angina. (Funded by the National Institute for Health and Care Research Imperial Biomedical Research Centre and others; ORBITA-2 ClinicalTrials.gov number, NCT03742050.).

Computer Simulation and Optimization of Cranial Vault Distraction

Objective:

The objective of this study was to validate the proof of concept of a computer-simulated cranial distraction, demonstrating accurate shape and end volume.

Design:

Detailed modeling was performed on pre- and postoperative computed tomographic (CT) scans to generate accurate measurements of intracranial volume. Additionally, digital distraction simulations were performed on the preoperative scan and the resultant intracranial volume and shape were evaluated.

Setting:

Tertiary Children’s Hospital.

Patients, Participants:

Preoperative and postoperative CT images were used from 10 patients having undergone cranial distraction for cephalocranial disproportion.

Interventions:

None; computer simulation.

Main Outcome Measure:

Computer simulation feasibility of cranial vault distraction was demonstrated through creation of digital osteotomies, simulating distraction through translating skull segments, followed by simulated consolidation. Accuracy of the model was evaluated through comparing the intracranial volumes of actual and simulated distracted skulls.

Results:

The developed digital distraction simulation was performed on the CT images of 10 patients. Plotting the relationship between the actual and simulated postdistraction volumes for the 10 patients yielded a slope of 1.0 and a correlation coefficient of 0.99. The average actual resultant volume change from distraction was 77.0 mL, compared to a simulated volume change of 76.9 mL.

Conclusions:

Digital simulation of cranial distraction was demonstrated through manipulation of the CT images and confirmed by comparing the actual to simulated volume change. This process may provide objective data in designing an individual distraction plan to optimize volume expansion and resultant cranial shape as well as patient education.

Inter-comparison of radon detectors for one to four week measurement periods

Seven different types of radon detectors (Atmos 12 dpx, RAD7, RStone, Sun Nuclear 1028, Ramon 2.2, Canary and CR-39) were compared for exposure periods of 1, 2, 3 and 4 weeks. The comparison was conducted under two conditions: (a) in a purpose-built radon chamber with an average radon concentration of 2560 Bq m(-3) (b) in a home environment with a radon concentration of 57 Bq m(-3), in both cases measured by the reference detector (Atmos 12 dpx) with a  ±10% uncertainty range. In (a) 5 out of 8 detectors recorded radon concentrations within the Atmos uncertainty range and all detectors recorded within  ±15%; in (b) 3 out of 9 detectors recorded within the Atmos uncertainty range and 6 out of 9 measured within  ±20%, for a 4 week measurement. The results from this study show that radon surveys can be conducted for shorter periods than the recommended 3 months where a rapid indication is needed of whether the radon concentration is above the reference level, such as when assessing the concentration during and after remediation work.

Design and performance of a small-animal imaging system using synthetic collimation

This work outlines the design and construction of a single-photon emission computed tomography imaging system based on the concept of synthetic collimation. A focused multi-pinhole collimator is constructed using rapid-prototyping and casting techniques. The collimator projects the centre of the field of view (FOV) through 46 pinholes when the detector is adjacent to the collimator, with the number reducing towards the edge of the FOV. The detector is then moved further from the collimator to increase the magnification of the system. The object distance remains constant, and each new detector distance is a new system configuration. The level of overlap of the pinhole projections increases as the system magnification increases, but the number of projections subtended by the detector is reduced. There is no rotation in the system; a single tomographic angle is used in each system configuration. Image reconstruction is performed using maximum-likelihood expectation-maximization and an experimentally measured system matrix. The system matrix is measured for each configuration on a coarse grid, using a point source. The pinholes are individually identified and tracked, and a Gaussian fit is made to each projection. The coefficients of these fits are used to interpolate the system matrix. The system is validated experimentally with a hot-rod phantom. The Fourier crosstalk matrix is also measured to provide an estimate of the average spatial resolution along each axis over the entire FOV. The 3D synthetic-collimator image is formed by estimating the activity distribution within the FOV and summing the activities in the voxels along the axis perpendicular to the collimator face.

Droperidol vs. prochlorperazine for the treatment of acute headache

To determine if droperidol i.v. is as effective as prochlorperazine i.v. in the emergency department (ED) treatment of uncomplicated headache, a randomized, controlled, blinded study was conducted in the Emergency Departments of two urban teaching hospitals. Patients >or= 18 years old with crescendo-onset headache were eligible for inclusion. Ninety-six patients (48 in each group) were randomized to receive droperidol 2.5 mg i.v. or prochlorperazine 10 mg i.v. Baseline characteristics were similar between the two study groups. For the main study outcome, 83.3% in the droperidol group and 72.3% in the prochlorperazine group reported 50% pain reduction at 30 min (p <.01; one-sided test of equivalence). The mean decrease in headache intensity was 79.1% (SD 28.5%) in the droperidol group and 72.1% (SD 28.0%) in the prochlorperazine group (p =.23). It is concluded that droperidol i.v. provided a similar reduction of headache as achieved with prochlorperazine i.v. with a similar incidence of akathisia.

Wrist arthrodesis with excision of the proximal carpal bones using the Ao/ASIF wrist fusion plate and local bone graft

We present our series of 17 patients who underwent wrist arthrodesis with excision of the proximal row carpal bones using the AO wrist fusion plate and local bone graft obtained from the excised proximal carpal row. All patients were evaluated using a questionnaire to assess pain, function, ability to perform an occupation and satisfaction with the procedure. The mean follow-up was 17 months, at which time all the fusions had united. Clinical outcome scores showed that 14 and 15 of the 17 patients achieved good or excellent results with regard to their current condition and clinical improvement, respectively. Four patients required secondary surgery, two for fractures and two for instability of the distal radio-ulnar joint unrelated to the wrist fusion.

A bait and switch hapten strategy generates catalytic antibodies for phosphodiester hydrolysis

General base catalysis supplied by the histidine-12 (H-12) residue of ribonuclease (RNase) A has long been appreciated as a major component of the catalytic power of the enzyme. In an attempt to harness the catalytic power of a general base into antibody catalysis of phosphodiester bond hydrolysis, the quaternary ammonium phosphate 1 was used as a bait and switch hapten. Based on precedence, it was rationalized that this positively charged hapten could induce a counter-charged residue in the antibody binding site at a locus suitable for it to deprotonate the 2'-hydroxyl group of the anhydroribitol phosphodiester substrate 2. After murine immunization with hapten 1, mAb production yielded a library of 35 antibodies that bound to a BSA-1 conjugate. From this panel, two were found to catalyze the cyclization-cleavage of phosphodiester 2. Kinetic studies at pH 7.49 (Hepes, 20 mM) and 25 degreesC showed that the most active antibody, MATT.F-1, obeyed classical Michaelis-Menten kinetics with a Km = 104 microM, a kcat = 0.44 min-1, and a kcat/kuncat = 1.7 x 10(3). Hapten 1 stoichiometrically inhibits the catalytic activity of the antibody. MATT.F-1 is the most proficient antibody-catalyst (1.6 x 10(7) M-1) yet generated for the function of phosphodiester hydrolysis and emphasizes the utility of the bait and switch hapten paradigm when generating antibody catalysts for processes for which general-base catalysis can be exploited.

Radiologic placement of long-term central venous peripheral access system ports (PAS Port): results in 150 patients

PURPOSE

The author reports experience with 150 peripheral access system ports (PAS Ports) placed in an interventional radiology suite. Complication rates from this series are compared with those of surgically placed tunneled catheters. The average cost of placement is compared with that of a surgically placed chest port.

PATIENTS AND METHODS

Findings were retrospectively reviewed in 150 patients in whom the PAS Port catheter was implanted. The age range was 26-84 years (mean, 46 years). The diagnoses in these patients included cancer (n = 68), acquired immunodeficiency syndrome (n = 52), osteomyelitis (n = 21), and abscess (n = 9). Implantation with use of fluoroscopic guidance and "Cath-finder" technology is described.

RESULTS

One hundred fifty ports have been indwelling for a total of 24,151 patient days (range, 40-220 days; mean duration, 161 days). Sepsis occurred in 3.3%, local infection in 5% (early infection 1%, late infection 4%), temporary catheter occlusion in 3.3%, postinsertion phlebitis in 7.3%, and venous thrombosis in 2%. The cost of radiologic PAS Port insertion averaged $1,488 versus $3,720 for surgical chest port insertion.

CONCLUSION

PAS Port central venous catheter placement by an interventional radiologist in this series is safe and cost effective and compares very favorably with surgery. Radiologists will likely see increasing requests by referring physicians for radiologically placed catheters and ports in this era of cost containment.

Utilization of temporary muscle paralysis to eliminate CT motion artifact in the critically ill patient

The intubated, critically ill patient often cannot suspend respiration long enough to eliminate severe computed tomographic (CT) motion artifact, even with current generation CT scanners. High quality, motion-free CT images were safely and easily obtained in two such patients using pancuronium bromide (Pavulon) to achieve muscle paralysis.

CT demonstration of pneumatosis intestinalis from bowel infarction

A case is presented that illustrates the value of CT in detecting pneumatosis intestinalis prior to plain film findings.

Thoracic and lumbar spine fusion: postoperative radiologic evaluation

A retrospective review of 206 consecutive thoracic and lumbar fusions revealed a variety of surgical procedures performed for instability and malalignment after severe trauma. Stabilization procedures included insertion of 103 Harrington distraction and 15 Harrington compression rods, 84 Weiss spings, six Luque rods, and 10 miscellaneous plates and wires as single or multiple devices in combination with anterior and/or posterior fusions. Complications of surgical fusion included nine unhooked rods, six fatigue fractures of rods and springs, five overdistractions of vertebrae, four cases of severe kyphosis, and two failures of reduction. A meaningful postoperative radiologic evaluation can be accomplished only when indications for surgical techniques, their radiologic appearance, and possible complications are known.

Reactions to intravenous contrast media. Part II: Acute renal response in euvolemic and dehydrated dogs

Growing concern about acute renal failure as the result of contrast agents prompted an investigation into the renal effects of intravenous contrast materials in euvolemic and dehydrated dogs. Bolus injection of hypertonic agents induced marked reductions in filtration fraction and glomerular filtration rate in both groups of animals; however, these changes were transient, returning to near-base-line values within 30 minutes after injection. The most striking differences between euvolemic and dehydrated animals appeared to be related to prerenal factors such as hypovolemia and contrast-induced hypotension.

Reactions to intravenous contrast media. Part I: Severe and fatal cardiovascular reactions in a canine dehydration model

Investigations into the nature of severe and fatal reactions to contrast media have been severely limited by their unpredictable occurrence in the clinical setting and the absence of suitable laboratory models. The authors report their experience with a canine dehydration model. Intravenous administration of 2 ml/kg of 76% sodium methylglucamine diatrizoate resulted in vomiting, shock, inappropriate slowing of the heart rate, and death. ECG findings indicated suppression of sinoatrial node automaticity, a decrease in the rate of atrioventricular conduction, and depression of myocardial contractility. These results suggest two possible mechanisms: (a) enhanced vagal tone as the result of stimulation of the vasomotor center of the medulla or (b) accentuation of direct contrast-induced myocardial toxicity.

Reappraisal of contrast media used to detect upper gastrointestinal perforations: comparison of ionic water-soluble media with barium sulfate

Iodinated water-soluble compounds have been widely recommended as the most suitable contrast media for diagnosis of gastrointestinal perforations. However, the authors present 6 cases in which mucosal tears and transmural perforations of the upper gastrointestinal tract were either unrecognizable or inadequately shown during initial evaluation with methylglucamine diatrizoate. Re-examination with barium sulfate demonstrated the precise location and extent of the perforations. Reasons for the higher diagnostic yield of barium studies are explained on the basis of experimental and clinical observations.

Evaluation of the urethra in males with spinal cord injury

Of 358 antegrade voiding urethrograms obtained in 200 males with spinal cord injury, the urethra was satisfactorily shown by 154 (77%), permitting evaluation of alterations related to cord damage, surgery, or iatrogenic trauma. In 105 cases the neurogenic urethra was normal, demonstrated only minor distension, or had a patulous appearance, in contrast to urinary tract changes such as a markedly neurogenic bladder, vesicoureteral reflux, and bladder calculi. In 49 patients, abnormalities included (a) changes related to surgical alleviation of sphincter dyssynergia; (b) iatrogenic changes such as diverticula strictures, undermining of the external sphincter ("spiral sign"), and intravasation of contrast material; and (c) pressure necrosis of the urethra. Some changes need no special treatment; others, such as pressure necrosis, require early recognition and prompt therapy.

Radiologic evaluation of surgical cervical spine fusion

Preoperative, intraoperative, and postoperative radiologic evaluation of surgical cervical spine fusion plays an integral part in the management of cervical spine injuries. The radiographic anatomy of the basic types of anterior, posterior, and combined fusions and the indications for their performance are discussed. A retrospective review of 210 consecutive cervical spine fusions showed a 21.1% radiographic complication rate for anterior fusions and only 3.9% for posterior fusions. The high complication rate of anterior fusions is related to the performance of anterior fusion in the presence of unrecognized posterior instability. Radiographically identified complications must be correlated with the clinical neurologic examination in each case since the spectrum of radiographic complications may be compatible with a clinically satisfactory result.