The Great Contrast Shortage of 2022-Lessons learnt in Australia.

INTRODUCTION: Computed tomography (CT) imaging is one of the most commonly used diagnostic tools. Iodine-based contrast media (IBCM) are frequently administered intravenously to improve soft tissue contrast in a wide range of CT scans. Supply chain disruptions triggered by the SARS-CoV-19 pandemic led to a global shortage of IBCM in mid-2022. The purpose of this study was to explore the impact of this shortage on the delivery of healthcare in Western Australia. METHODS: We performed a single-centre retrospective analysis of the provision of CT studies, comparing historical patterns to the shortage period. We focussed our attention on the total number of CT scans (noncontrast CT [NCCT] and contrast-enhanced CT [CECT]) and also specifically CT pulmonary angiogram (CTPA) and CT neck angiogram with or without inclusion of circle of Willis (CTNA) examinations. We also examined whether a decrease was compensated by increasing frequency of alternate examinations such as ventilation/perfusion (V/Q) scans, carotid Doppler ultrasound studies and Magnetic Resonance Angiograms (MRAs). RESULTS: Since 2012, there has been an approximate linear increase in the frequency of CT examinations. During the period of contrast shortage, there was an abrupt drop-off by approximately 50% in the CECT, CTPA and CTNA groups compared with the preceding 6 weeks (49%, 55% and 44%, respectively, with P < 0.001 in all cases). During the contrast shortage, the frequency of V/Q scans increased fivefold (from 13 to 65; P < 0.001). However, the provision of carotid Doppler ultrasound studies and MRAs remained approximately stable in frequency across recent time intervals. CONCLUSION: Our findings demonstrate that the IBCM shortage crisis had a very significant impact on the delivery of healthcare. While V/Q scans could (partially) substitute for CTPA studies in suspected pulmonary emboli, there appeared to be no valid alternative for CTNA studies in stroke calls. The unexpected and critical shortage of IBCM forced healthcare professionals to conserve resources, prioritise indications, triage patients based on risk, explore alternate imaging strategies and prepare for similar events recurring in the future.

The Adrenal Vein Sampling Outcomes Study (AVOS): success rates following adrenalectomy for unilateral primary aldosteronism.

The objective was to determine the clinical and biochemical success rates and assess the nature of follow-up after adrenalectomy in patients with unilateral primary aldosteronism (PA), subtyped by adrenal vein sampling (AVS) in West Australia (WA) using the Primary Aldosteronism Surgical Outcome (PASO) criteria. Clinical and biochemical outcomes were retrospectively evaluated in patients with unilateral PA who underwent adrenalectomy according to AVS between September 2017 and September 2020. Pre- and post-surgical data were collected using a standardised questionnaire, review of clinic letters and examination of private and public pathology results and radiological reports. Follow-up data were available for 47 patients post-adrenalectomy; biochemical outcome data were available for 37 patients, clinical outcome data for 40 patients, with 30 patients having both outcomes available. Final assessment was performed between 0 to 3 months in 23/37 (62.2%) patients with biochemical outcomes, 15/40 (37.5%) with clinical outcomes, and 17/30 (56.7%) with both clinical and biochemical outcomes. Complete biochemical success was achieved in 83.8% (31/37) of patients, with 26.7% (8/30) obtaining both complete clinical and biochemical success. Complete clinical success was achieved in 35.0% (14/40) of patients, with 47.5% (19/40) obtaining partial clinical success. Overall, 93.6% (44/47) of patients derived benefit from adrenalectomy. The outcomes of adrenalectomy for unilateral PA in Western Australian using standardised PASO criteria demonstrate highly comparable clinical and biochemical success rates to international data. However, further standardisation of post-operative follow-up care needs to be implemented to ensure the recommended repeat follow-up assessment criteria are collected.

Role of the sympathetic nervous system in cardiometabolic control: implications for targeted multiorgan neuromodulation approaches.

Sympathetic overdrive plays a key role in the perturbation of cardiometabolic homeostasis. Diet-induced and exercise-induced weight loss remains a key strategy to combat metabolic disorders, but is often difficult to achieve. Current pharmacological approaches result in variable responses in different patient cohorts and long-term efficacy may be limited by medication intolerance and nonadherence. A clinical need exists for complementary therapies to curb the burden of cardiometabolic diseases. One such approach may include interventional sympathetic neuromodulation of organs relevant to cardiometabolic control. The experience from catheter-based renal denervation studies clearly demonstrates the feasibility, safety and efficacy of such an approach. In analogy, denervation of the common hepatic artery is now feasible in humans and may prove to be similarly useful in modulating sympathetic overdrive directed towards the liver, pancreas and duodenum. Such a targeted multiorgan neuromodulation strategy may beneficially influence multiple aspects of the cardiometabolic disease continuum offering a holistic approach.

Improved technical success and radiation safety of adrenal vein sampling using rapid, semi-quantitative point-of-care cortisol measurement.

Objective Primary aldosteronism is a curable cause of hypertension which can be treated surgically or medically depending on the findings of adrenal vein sampling studies. Adrenal vein sampling studies are technically demanding with a high failure rate in many centres. The use of intraprocedural cortisol measurement could improve the success rates of adrenal vein sampling but may be impracticable due to cost and effects on procedural duration. Design Retrospective review of the results of adrenal vein sampling procedures since commencement of point-of-care cortisol measurement using a novel single-use semi-quantitative measuring device for cortisol, the adrenal vein sampling Accuracy Kit. MEASUREMENTS: Success rate and complications of adrenal vein sampling procedures before and after use of the adrenal vein sampling Accuracy Kit. Routine use of the adrenal vein sampling Accuracy Kit device for intraprocedural measurement of cortisol commenced in 2016. Results Technical success rate of adrenal vein sampling increased from 63% of 99 procedures to 90% of 48 procedures ( P = 0.0007) after implementation of the adrenal vein sampling Accuracy Kit. Failure of right adrenal vein cannulation was the main reason for an unsuccessful study. Radiation dose decreased from 34.2 Gy.cm2 (interquartile range, 15.8-85.9) to 15.7 Gy.cm2 (6.9-47.3) ( P = 0.009). No complications were noted, and implementation costs were minimal. Conclusions Point-of-care cortisol measurement during adrenal vein sampling improved cannulation success rates and reduced radiation exposure. The use of the adrenal vein sampling Accuracy Kit is now standard practice at our centre.

Deep circumflex iliac artery as a cause of type II endoleak.

PURPOSE: To report a collateral pathway involving the deep circumflex iliac artery causing a type II endoleak following endoluminal exclusion of an abdominal aortic aneurysm (AAA). CASE REPORT: A 75-year-old man was investigated for a persistent type II endoleak 2 years after endovascular AAA repair with a Zenith Trifab stent-graft. Angiography revealed contrast in the sac from a lumbar artery fed via a collateral of the deep circumflex iliac artery. The lumbar artery was embolized with coils, but an endoleak persisted and is being followed. CONCLUSIONS: This collateral pathway is easily missed during angiography for endoleaks and should be considered where an endoleak is suspected but cannot be found.

Spontaneous common iliac artery dissection after exercise.

PURPOSE: To review the clinical features and management of spontaneous iliac dissections. CASE REPORT: A healthy 60-year-old competitive cyclist presented with acute onset of short-distance claudication following vigorous exercise. Angiography showed a dissection flap extending from the right common iliac artery to the external iliac artery. An uncovered stent was placed across the proximal entry site but did not obliterate the false lumen; open surgical intervention was required. CONCLUSIONS: Spontaneous dissection of the iliac artery is a rare but important condition to suspect in high performance athletes complaining of leg pain following exercise.

Chronic renal vein thrombosis in a renal allograft.

Acute renal vein thrombosis in a renal allograft is uncommon and usually occurs in the post-transplant period. Chronic renal vein thrombosis can occur insidiously many years after transplant without significant deterioration in renal allograft function or symptoms.