ETD system

Electronic theses and dissertations repository


Tesi etd-10092019-071202

Thesis type
Tesi di specializzazione (4 anni)
Diagnostic accuracy of instantaneous free-wave ratio (iFR) for the assessment of myocardial ischemia in stable coronary artery disease and non-ST segment elevation acute coronary syndrome: a comparison with non-invasive stress imaging.
Corso di studi
relatore Prof. Pedrinelli, Roberto
correlatore Prof.ssa Petronio, Anna Sonia
correlatore Dott. De Carlo, Marco
Parole chiave
  • CAD
  • FFR
  • physiological assessment of coronary stenosis
  • iFR
Data inizio appello
Secretata d'ufficio
Data di rilascio
Riassunto analitico
In patients with chronic coronary syndrome or low-risk NSTEASC, revascularization according to evidence of myocardial ischemia is recommended. Instantaneous wave-free ratio (iFR) is an alternative method to evaluate pressure drift among an epicardial stenosis and then its hemodynamic significance without need of hyperemia. Compared with FFR iFR is less time consuming and does not need use of vasodilator agents.
The aim of our study was to assess the diagnostic accuracy of iFR with respect to the identification of coronary epicardial stenoses causing ischemia as identified by non invasive imaging stress test (NIST).
Seventy-one patients were recruited in the study and 122 vessels were evaluated. On a per-vessel analysis, in 56.7% vessels there were concordance between iFR and ischemic territories detected by NIST. In 21.3% vessels, we found no ischemia at NIST and positive iFR. In 23.0% vessels iFR was negative while ischemia was demonstrated by NIST in the same vascular territory.
Combining the anatomical information of the coronary angiography with the functional information of the NIST we obtained a standard reference for the identification of coronary epicardial stenoses causing ischemia. We use this standard reference to assess diagnostic accuracy of iFR. We found a sensibility, specificity, PPV, NPV and accuracy respectively of 96.5%, 75.0%, 73.3%, 96.7% and 84.4%. Among lesions of intermediate severity (50-90%) and discordant results between NIST and iFR, treatment strategy was based on iFR results. Sixty-seven (94%) patients were followed-up for a mean of 22.8┬▒17.6 months. The composite endpoint of MACE occurred in 16.41% and a combined end-point of death and myocardial infarction occurred in 11.9% patients. Stratification in four groups according to the per-patient concordance between iFR and NIST was performed and no significant differences in rate of MACE (p=0.50) and composite end-point of MI-death (p=0.20) was found. Dividing population into two groups, according to positivity of iFR, we found no differences in rate of MACE (11.9% vs. 4.47% p=0.14), but we found that patient with iFR>0.89 were at lower risk of MI and death respect of the positive-iFR group (11.9% vs. 0%, p=0.047).
The diagnostic accuracy of iFR for assessment of myocardial ischemia is good when compared with a combined angiographic and non-invasive imaging stress test information as a reference standard. Giving a per-vessel assessment, iFR can help operator to decide whether to treat or defer revascularization of intermediate stenosis severity. This therapeutic strategy seems to be safe as described in large multicentric trials.