A “normal” invasive coronary angiogram may not be normal

Risk of Myocardial Infarction in Patients Without Angiographic Coronary Artery Disease Compared With the General Population

We examined the 10-year risk of myocardial infarction (MI) and death in patients without obstructive coronary artery disease (CAD) compared with the general population. We conducted a cohort study of every patient without obstructive CAD by coronary angiography (CAG) between 2003 and 2016 in Western Denmark. Patients were matched by gender and age with individuals from the general population of Western Denmark with no history of CAD. End points were MI and death. Ten-year risk differences in cumulative incidence proportions were computed, accounting for the competing risk of death in the case of MI. Unadjusted and adjusted incidence rate ratios (aIRRs) were estimated using conditional Poisson regression. We included 46,467 patients and 234,654 individuals from the general population. Median follow-up was 7.7 years. The 10-year cumulative incidence of MI was 2.40% (95% confidence interval [CI] 2.24 to 2.57) in patients without obstructive CAD in the CAG and 2.70% (95% CI 2.62 to 2.78) in the general population, with a reduced absolute 10-year risk (risk difference -0.30%, 95% CI -0.49 to -0.12) and a reduced aIRR (aIRR 0.70, 95% CI 0.63 to 0.77). Ten-year mortality was higher in patients without obstructive CAD in the CAG (21.44%, 95% CI 20.99 to 21.89) compared with the general population (17.25%, 95% CI 17.06 to 17.44). However, mortality rates were similar after adjustment (aIRR 1.00, 95% CI 0.96 to 1.02). In conclusion, the absence of obstructive CAD according to CAG is associated with a lower risk of MI than in the general population, and similar 10-year mortality.

Coronary CT Angiography Derived Fractional Flow Reserve: The Game Changer in Noninvasive Testing

PURPOSE OF REVIEW

To summarize the scientific basis of CT derived fractional flow reserve (FFR_CT) and present an updated review on the evidence from clinical trials and real-world observational data RECENT FINDINGS: In prospective multicenter studies of patients with stable coronary artery disease (CAD), FFR_CT showed high diagnostic performance. More recently, FFR_CT has advanced to the realm of clinical utility and real-world clinical practice with emerging data showing that FFR_CT when compared to standard care is efficient in safely reducing downstream utilization of invasive coronary angiography (ICA), and costs, as well as improving the diagnostic yield of ICA. Moreover, FFR_CT may broaden applicability of frontline coronary CTA testing to patients with high pre-test risk of CAD. Introducing FFR_CT into clinical practice has the potential to significantly improve the management of patients with stable CAD. The optimal FFR_CT testing interpretation strategy, as well as the relative cost-efficiency of FFR_CT against standard noninvasive functional testing, need further investigation.

Effect of the ratio of coronary arterial lumen volume to left ventricle myocardial mass derived from coronary CT angiography on fractional flow reserve

BACKGROUND

We hypothesize that in patients with suspected coronary artery disease (CAD), lower values of the ratio of total epicardial coronary arterial lumen volume to left ventricular myocardial mass (V/M) result in lower fractional flow reserve (FFR).

METHODS

V/M was computed in 238 patients from the NXT trial who underwent coronary computed tomography angiography (CTA), quantitative coronary angiography (QCA) and FFR measurement in 438 vessels. Nitroglycerin was administered prior to CT, QCA and FFR acquisition. The V/M ratio was quantified on a patient-level from CT image data by segmenting the epicardial coronary arterial lumen volume (V) and the left ventricular myocardial mass (M). Calcified and noncalcified plaque volumes were quantified using semi-automated software.

RESULTS

The median value of V/M (18.57 mm³/g) was used to define equal groups of low and high V/M patients. Patients with low V/M had greater diameter stenosis by QCA, more plaque and lower FFR (0.80 ± 0.12 vs. 0.87 ± 0.08; P < 0.0001) than those with high V/M. A total of 365 vessels in 202 patients had QCA stenosis ≤50% and measured FFR. In these patients, those with low V/M had higher percent diameter stenosis by QCA, greater total plaque volume and lower FFR (0.81 ± 0.12 vs. 0.88 ± 0.07; P < 0.0001) than those with high V/M. In multivariate logistic regression analysis, V/M was an independent predictor of FFR ≤0.80 (all p-values < 0.001).

CONCLUSIONS

Patients with a low V/M ratio have lower FFR overall and in non-obstructive CAD, independent of plaque measures.