In Timor-Leste, cardiac interventions and surgical procedures are largely provided by the East Timor Hearts Fund. Since March 2020, no Timorese patients have been able to travel to Australia for humanitarian cardiac procedures.

Pre-COVID, intermediate risk ACS accounted for ∼50% of our local cardiac medical assessment unit (MAU) admissions and followed an inpatient pathway for further investigation. During COVID, a new protocol was established with the aim to reduce the burden on inpatient cardiac and imaging resources, where intermediate-risk ACS patents were discharged direct from ED with arrangements made for an expedited outpatient CTCA. The current study aim was to compare the allocation of hospital resources, completion, and timing of CTCA in the two models of care. Retrospective cohort study comparing the characteristics and resource allocation of consecutive intermediate-risk ACS patients who went onto undergo CTCA pre- and post-COVID. The decision to investigate with CTCA was made at the discretion of the treating Cardiologist. ED and total inpatient length of stay and the cost in National Weighted Activity Units (NWAU), which is a common unit for measuring hospital activity, were compared. 78 consecutive patients were included (Table). All 39 patients in Group 1 had inpatient CTCA. 36/39 patients attended their arranged CTCA (2 patients failed to attend, 1 patient represented to hospital). An expedited outpatient protocol for investigation of Intermediate-risk ACS was associated with significant reduction in total inpatient length of stay and associated costs, albeit with a significant delay in the time to diagnosis. Further examination into associated patient outcomes is warranted.Tabled 1Group 1 (Pre-COVID, 2019)Group 2 (Post-COVID, 2020)P valueAge59 (42-71)59 (51-66)0.84Male sex19 (48.7%)20 (51.3%)0.82Heart Score3(2-4)3 (2-4)0.99ED LOS5 hours 25 minutes (3:41-9:44)5 hours 20 minutes (3:54-7:53)0.94Time to CTCA23 hours 35 minutes (15:17-40:17)4 days (2-5.5)<0.001Total inpatient LOS29 hours 39 minutes (19:35-51:15)5 hours 28 minutes (3:54-8)<0.001Total NWAU$1810 ($1634-3024)$1023.02 ($0-1571)<0.001 Open table in a new tab

Background: Computed tomographic coronary angiography (CTCA) is a non-invasive alternative to invasive coronary angiography (ICA) for detecting in-stent restenosis (ISR). The recently developed high definition (HD), CTCA machine, the 64-slice Discovery 75-HD (GE), has greater spatial resolution than standard definition (SD) CTCA. Aim: We compare the accuracy of HD and SD CTCA in detecting ISR using ICA as the gold standard. Method: A retrospective study of CTCA and ICA data for 37 patients (with 57 stented segments) was made. Reconstructed CTCA images were assessed for image quality (IQ) scores and whether binary ISR (>50%) was present. ICA was analysed using quantitative coronary angiography. Results were compared for sensitivity, specificity, PPV and NPV. Patient and stent factors were also examined. Results: HD CTCA had significantly fewer non-diagnostic stented segment images than SD CTCA (HD 11%, SD 33%; p = 0.046). With non-diagnostic studies excluded, HD and SD CTCA had identical sensitivity (100%) and specificity (94%) in detecting ISR. Both HD and SD had good PPV (88%, 75%), NPV (100%, 100%), and accuracy (96%, 95%). Including non-diagnostic CTCA studies, accuracy for HD and SD fell to 85% and 67% respectively. IQ scores were significantly lower for smaller stents (diameter <3 mm) and overweight patients (BMI > 25). Conclusions: HD CTCA has a greater proportion of diagnostic images than SD CTCA. However when image quality is adequate, both HD and SD CTCA are highly accurate. Thus, CTCA can be used to assess stented patients for ISR, and ICA may be needed only if CTCA images are non-diagnostic.

Background: Current practice of only determining % stenosis in coronary angiography (CA) underestimates the extent of coronary artery disease (CAD). CTCA has shown that CAD extent has important prognostic value. However, scoring systems to estimate CAD extent are not used clinically and correlations between different scores are unclear. Aim: We studied the extent of CAD using five scoring systems, and compared measurements made on CTCA with invasive CA (IVCA). Method: In 54 consecutive patients who underwent both CTCA and IVCA within six weeks, we measured vessel score (VS: 0–3 vessel with stenosis >70%), and four CAD extent scores: calcium (CAC), CAP-CT (CAP), modified Gensini (MGS) and extent (EXT) scores. All scores were measured in both CTCA and IVCA, except for CAC (only CTCA). Results: VS were 0 (n = 27), 1 (n = 19), 2 (n = 6), and 3 (n = 2). CAP, MGS and EXT by CTCA correlated with the corresponding score as determined by IVCA (r = .65, .67, and .56, respectively, p < 0.01). All four CAD extent scores correlated moderately with each other. However, when comparing the four extent scores between patients without (VS = 0) or with (VS = 1, 2 or 3) severe stenoses, we found VS correlated only with MGS but not with CAC, CAP nor EXT. Conclusions: We showed that CTCA and IVCA give comparable CAD extent scores. CAC, CAP and EXT do not correlate with VS, and further stratify patients without significant CAD (VS = 0) into higher and lower risk groups. Thus, use of CAP or EXT, in addition to CAC, can improve the prognostic value of CA.

Concern about radiation exposure during CT coronary angiography (CTCA) has limited its use and application. Most multislice CT scanners utilise dose modulated retrospective helical acquisition (RG) to reduce the high radiation exposure which may occur in some patients. A new alternative imaging mode is the axial “step and shoot” acquisition known as prospective gating (PG).

Background: Patients with low calcium scores (CS) considered to be at low risk for cardiac events are often reassured, and not usually considered for lipid lowering therapy. A low CS, however, does not preclude the finding of non-calcified plaque (NCP) and even ischaemia. The earlier detection of NCP by newer generation MDCT systems may play an increasing role in more accurately determining true cardiac risk by providing a more reliable estimation of overall plaque burden beyond the mere assessment of calcium.

Background: Non-invasive assessment of patients who have previously undergone coronary artery bypass surgery using traditional techniques has limitations. MDCT coronary angiography is emerging as a useful non-invasive technique to assess these patients. Earlier scanners had difficulty evaluating all grafts due to artefact and poor opacification.

Introduction: Coronary calcification produces high-density artefacts which limit MDCT angiographic assessment of coronary arteries. Sixty-four-slice MDCT coronary angiography has demonstrated a high diagnostic accuracy in patients without heavy calcification.

Background: TOE guided agitated saline bubble study with adequate provocation is the current gold standard to detect right to left cardiac shunts. TOE carries potential risks and provocation may be unsatisfactory in the sedated patient. Agitated Gelofusine provides greater opacification of the cardiac chambers compared with agitated saline.