Hypertension attenuates the prognostic value of coronary artery calcification scoring in low-risk patients.

OBJECTIVES: In outpatients with suspected ischaemic symptoms, we investigated the impact of risk factor profile on the prognostic value of coronary artery calcium scoring (CACS) and CT coronary angiography (CTCA). METHODS: 772 consecutive patients underwent CACS and CTCA; 52 patients (6.7%) with significant coronary artery lesions underwent revascularisation within 60 days and were excluded. 720 remaining patients were followed up for 38.1±17.4 months. RESULTS: Late presentation (after 60 days) major adverse cardiovascular events (MACEs) were recorded in 27 patients (3.8%). Hypertension was strongly associated with adverse outcomes (unadjusted HR 6.5 (2.9 to 14), p<0.001), and hypertensive patients had double the prevalence of non-calcified plaque versus normotensive individuals (30.2% vs 14.3%, p<0.001). Adjusting for confounders, severe stenosis at CTCA was predictive of MACE for normotensive and hypertensive patients (HR 9.6 (2.8 to 43.1), p<0.001, and HR 6.2 (2.4 to 16.1), p<0.001, respectively). CACS alone was not predictive of MACE throughout the cohort (HR 1.001 (0.9997 to 1.001), p=0.36) and when adjusting for confounders, a cut-off of CACS>400 predicted MACE in normotensive individuals (HR 10.6 (2.41 to 49.3), p<0.001) but not in hypertensive individuals (HR 1.3 (0.5 to 3.6), p=0.56). Zero calcium score did not mitigate the risk of MACE (HR 0.84 (0.39 to 1.8), p=0.65) and 13/27 patients (48.1%) who suffered MACE had a 0 calcium score; all had hypertension. CONCLUSIONS: In low-risk patients with stable cardiovascular symptoms, CTCA provides important additive prognostic information over CACS, and CACS (including CACS>400) underestimated cardiovascular risk in patients with hypertension. This may relate to the increased prevalence of non-calcified plaque in these individuals.

Inconsistency in aortic stenosis severity between CT and echocardiography: prevalence and insights into mechanistic differences using computational fluid dynamics.

Objectives: The aims of this study were to evaluate the inconsistency of aortic stenosis (AS) severity between CT aortic valve area (CT-AVA) and echocardiographic Doppler parameters, and to investigate potential underlying mechanisms using computational fluid dynamics (CFD). Methods: A total of 450 consecutive eligible patients undergoing transcatheter AV implantation assessment underwent CT cardiac angiography (CTCA) following echocardiography. CT-AVA derived by direct planimetry and echocardiographic parameters were used to assess severity. CFD simulation was performed in 46 CTCA cases to evaluate velocity profiles. Results: A CT-AVA>1 cm2 was present in 23% of patients with echocardiographic peak velocity≥4 m/s (r=-0.33) and in 15% patients with mean Doppler gradient≥40 mm Hg (r=-0.39). Patients with inconsistent severity grading between CT and echocardiography had higher stroke volume index (43 vs 38 mL/m2, p<0.003) and left ventricular outflow tract (LVOT) flow rate (235 vs 192 cm3/s, p<0.001). CFD simulation revealed high flow, either in isolation (p=0.01), or when associated with a skewed velocity profile (p=0.007), as the main cause for inconsistency between CT and echocardiography. Conclusion: Severe AS by Doppler criteria may be associated with a CT-AVA>1 cm2 in up to a quarter of patients. CFD demonstrates that haemodynamic severity may be exaggerated on Doppler analysis due to high LVOT flow rates, with or without skewed velocity profiles, across the valve orifice. These factors should be considered before making a firm diagnosis of severe AS and evaluation with CT can be helpful.

'Porcelain aorta': a proposed definition and classification of ascending aortic calcification.

Introduction: 'Porcelain aorta' is listed in the second consensus document of the Valve Academic Research Consortium as a risk factor in aortic valve replacement. However, the extent of circumferential involvement is poorly defined with great variability in reported incidence. We present a simple, reproducible classification to describe the extent of aortic calcification and thus appropriately define 'porcelain aorta', aiding clinical decision-making and registry data collection. Methods: 175 consecutive CT aortograms were reviewed. The aorta was divided into three sections, and each section divided into quadrants. These were individually scored using a 5-point scale (0-no calcification, 5-complete contiguous calcification).Results for each quadrant were summated for each segment to provide an indication of the distribution of calcification. Results: Only one patient (0.6%) had a 'true' porcelain aorta, defined as contiguous calcification across all quadrants at any aortic level. Intraobserver and interobserver variation was excellent for the ascending aorta (K=0.85-0.88 and 0.81-0.96, respectively) while the interobserver variation in the transverse arch was good at 0.75. Conclusions: Our data suggest the incidence of 'true' porcelain aorta may be significantly lower than reported in the literature. The predominance of calcification within the anterior wall of the proximal ascending aorta and the superior wall of the transverse arch may be clinically important. Application of this quick, simple and reproducible grading system, with no requirement for advanced software, may provide a tool to support accurate assessment of focal aortic calcification and its relationship to subsequent procedural risk.

Clinical outcomes when applying NICE guidance for the investigation of recent-onset chest pain to a rapid-access chest pain clinic population.

OBJECTIVE: To describe the clinical outcomes of patients for whom National Institute for Health and Care Excellence (NICE) recent-onset chest pain guidance would not have recommended further investigation, compared with those of patients where further investigation would have been recommended. METHODS: 557 consecutive patients with recent-onset chest pain attending rapid-access chest pain clinics (RACPC) in two district general hospitals over a 9-month period were retrospectively reviewed. Likelihood of coronary artery disease (CAD) was calculated according to NICE-defined modified Diamond-Forrester criteria. Patients were categorised into those for whom NICE guidelines recommend (NICE-Y) and do not recommend (NICE-N) further investigation. Main outcome measures were subsequent diagnosis of significant CAD and major adverse cardiac events (MACE) at 6 months. RESULTS: 187/557 (33.6%) patients comprised NICE-Y group, with 370/557 (66.4%) in NICE-N group. 360/370 (97.3%) of NICE-N group would have been excluded from further investigation due to non-anginal chest pain. Of 92/557 (16.5%) patients subsequently diagnosed with significant CAD, 35/557 (9.5%) were from NICE-N group versus 57/557 (30.5%, p<0.0001) from NICE-Y group. Of 11 patients experiencing at least one MACE, 7/557 (1.9%) were from NICE-N group, versus 4/557 (2.1%, p=1.000) from NICE-Y group. CONCLUSIONS: The rigid application of NICE chest pain guidance to a RACPC population may result in up to two-thirds of patients being excluded from further cardiac investigation. Potentially, up to 10% of these patients may subsequently be diagnosed with significant CAD, with up to 2% potentially experiencing a major adverse cardiac event.