Recurrent Angina and Prognosis after Coronary Computed Tomography Angiography: Associations with FFRCT and Coronary Plaque Characteristics -A 3-Year follow-up in Patients with Stable Angina

Kristian Tækker Madsen*

*Corresponding author for this work

Research output: ThesisPh.D. thesis

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Abstract

Stable angina pectoris (SAP) is a condition characterized by recurrent chest pain or dyspnea caused by an imbalance in oxygen supply and myocardial demand, typically due to flow limiting coronary artery disease (CAD). There is a plethora of conditions that may cause chest pain indistinguishable from SAP and as such it is a clinical challenge to select the optimal treatment for the individual patient. In Denmark it is recommended that all patients with suspected new onset SAP undergo coronary computed tomography angiography (CTA). These recommendations are based on the excellent capability of CTA to rule-out the presence of significant CAD and to rule-in the presence of severe CAD necessitating up-front invasive assessment. The pitfall of CTA is a tendency to overestimate severity of coronary stenosis in the intermediate to moderate range (30-90%). In contemporary practice this discrepancy can be overcome by the performance of fractional flow reserve derived from CTA (FFRCT), which enables precise simulated calculations of pressure and flow across the entire coronary tree based on the CTA image data. However, it is currently unknown if the flow calculations provided by FFRCT are associated with risk of recurrent angina and whether they may help guide and individualize the treatment of patients with SAP. Furthermore, due to the relatively recent introduction of FFRCT, the majority of prognostic data relating to FFRCT is restricted to1-year follow-up periods and long-term data is warranted.

The two main purposes of this Ph.D. project was: 1)To assess the association between FFRCT and recurrent angina and 2) to assess the prognostic value of FFRCT in patients with new onset SAP and coronary stenosis by CTA for up to 3-years.

Manuscript I evaluated the association between recurrent angina at 1-year follow-up and various FFRCT interpretation algorithms. We found that FFRCT algorithms which reflected the cumulative sum of flow limitation across the entire vessel(nadir FFRCT) were superior to algorithms which only assessed the focal flow limitation pertaining to the stenosis (lesion-specific FFRCT).

Manuscript II evaluated the association between lesion-specific FFRCT and 3-year risk of hard end points (mortality and myocardial infarction). We observed that patients with a normal FFRCT had an excellent prognosis and although patients with abnormal FFRCT only constituted 42% of the entire population, they accounted for 87% of all registered adverse cardiovascular events. Furthermore, the addition of FFRCT to models containing baseline risk variables (diabetes, hypertension, dyslipidemia and smoking) and morphological parameters derived from CTA (degree of stenosis and coronary artery calcium score) enhanced the overall discrimination of endpoints.

Manuscript III assessed the association between nadir FFRCT and long-term recurrent angina at 3-year follow-up. We observed that an abnormal FFRCT was associated with an increased risk of recurrent angina compared to a normal FFRCT, unless revascularization had been performed in all vessels with abnormal FFRCT, in which case the risk was similar to patients with normal FFRCT. Furthermore, we quantified the impact of recurrent angina on quality of life and found that patient groups with the highest incidence of recurrent angina also reported the lowest quality of life.

Manuscript IV assessed the association between revascularization, lesion-specific FFRCT and risk of cardiovascular death and myocardial infarction. We observed that patients with normal FFRCT and those in whom all vessels with abnormal FFRCT had been revascularized early (within 90 days of the initial CTA scan) had a similar favorable prognosis. On the other hand, patients in whom one or more vessels with abnormal FFRCT were nonrevascularized had an increased risk of cardiovascular death and myocardial infarction.

Based on this, we conclude that in patients with SAP and coronary stenosis by CTA a normal FFRCT test result predicts favorable outcomes in terms of both symptoms, quality of life and adverse cardiovascular events. In patients with abnormal FFRCT the degree of revascularization may be associated with symptoms as well as prognosis.
Original languageEnglish
Awarding Institution
  • University of Southern Denmark
Supervisors/Advisors
  • Sand, Niels Peter R., Principal supervisor
  • Nørgaard, Bjarne Linde, Co-supervisor
  • Dey, Damini, Co-supervisor, External person
Date of defence31. May 2024
Publisher
Publication statusPublished - 17. Apr 2024

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