CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 4, September/October 2023 248 AFRICA The importance of baseline fractional flow reserve to detect significant coronary artery stenosis in different patient populations Ismet Zengin, Alper Karakus Abstract Introduction: Fractional flow reserve (FFR) assessment compares the blood flow on either side of a blockage in the coronary artery and indicates how severe the stenosis is in the artery. Intravenous adenosine is widely used to achieve conditions of stable hyperaemia for the measurement of FFR. However, intravenous adenosine affects both systemic and coronary vascular beds differentially. Therefore, FFR has some limitations, such as the side effects of adenosine and the long procedure time. In addition, there are not enough studies on the evaluation of the baseline ratio of distal coronary pressure to aortic pressure (Pd/Pa) according to standard cut-off values in coronary stenosis under special clinical conditions. This study aimed to assess the diagnostic power of the baseline FFR value for critical coronary stenosis and to determine its predictive value in special patient groups. Methods: This retrospective study included 158 patients, who were stratified as Q1 (< 0.89), Q2 (0.89–0.92), Q3 (0.93–0.95) and Q4 (> 0.95) based on baseline FFR values. The baseline Pd/Pa value, the change in adenosine FFR and the raw FFR change were recorded. Its predictive value was also calculated for specific patient groups. Results: The threshold value of baseline FFR level for predicting critical stenosis was ≤ 0.92 with a sensitivity of 92.8% and a specificity of 82% (upper limit of Q2 cartilage). Patients with a baseline FFR value ≤ 0.92 had a 58.4-fold greater likelihood of a critical outcome compared with patients with a baseline FFR value > 0.92 (OR: 58.4; 95% CI: 20.3–124.6). In patients with a baseline FFR ≤ 0.92, the Q1 group had a 10.23-fold higher odds of critical stenosis compared with the Q2 group (OR: 10.23; 95% CI: 2.14–48.84). The same values had similar diagnostic power for all specific patient groups. Conclusion: The baseline FFR value could be used to predict critical coronary stenosis in our patients and had similar value for predicting lesion severity in all the subgroups. Keywords: fractional flow reserve, coronary artery disease, baseline Pd/Pa, adenosine Submitted 27/6/23, accepted 23/8/23 Published online 21/9/23 Cardiovasc J Afr 2023; 34: 248–254 www.cvja.co.za DOI: 10.5830/CVJA-2023-045 Clinical studies and evidence on fractionated flow reserve (FFR), which is widely used in the physiological assessment of coronary stenosis, are growing more numerous. Intravenous adenosine is widely used to achieve conditions of stable hyperaemia for the measurement of FFR. If we review the results of FFR studies, we see that the researchers have used different methods, which gave different results. This can lead to confusion in clinical practice. In addition, certain agents may create some risks to patients. For instance, the commonly used adenosine has side effects, including transient atrioventricular (AV) block, chest pain and dyspnoea.1 In adenosine FFR, depending on the route of administration (for example, intravenous infusion), the duration of the procedure may be prolonged and patients may be exposed to risks related to the longer duration. Given these limitations of FFR, other methods of assessment have come to the forefront. One of these is measuring the baseline ratio of the coronary pressure distal to the coronary lesion to the aortic pressure (Pd/Pa), which is performed without the use of a hyperaemic agent. There are studies evaluating the correlation of the Pd/Pa ratio with the FFR value using hyperaemic agents.1-3 In parallel, the instantaneous wave-free ratio (iFR), which is a haemodynamic assessment that makes use of initial pressure values, requires separate equipment and software, which may not be cost effective. It is generally accepted that the Pd/Pa ratio, which can be expressed as the basal FFR value, is not influenced by many parameters. Nevertheless, there are not enough subgroup analyses of basal FFR measurements. Data on the use of Pd/Pa values obtained from previous studies in different patient populations are lacking. The aim of this study was to evaluate the diagnostic power of the baseline FFR value for critical coronary stenosis and to determine its predictive value in special patient groups. Methods This retrospective study included 158 patients with 158 lesions who underwent FFRmeasurement between July 2019 and January 2023 at the Bursa City Hospital, Bursa, Turkey. FFR was planned to be performed in patients with acute coronary syndrome five days after treatment of the responsible lesion or in patients with chronic coronary syndrome with persistent symptoms despite optimal medical treatment and with 50–90% anatomical stenosis on conventional coronary angiography (CAG). Department of Cardiology, Bursa City Hospital, Health Sciences University, Bursa, Turkey Ismet Zengin, MD, ismetzengin48@hotmail.com Department of Cardiology, Bursa Yüksek Ihtisas Training and Research Hospital, Health Sciences University, Bursa, Turkey Alper Karakus, MD
RkJQdWJsaXNoZXIy NDIzNzc=