Impact of fractional flow reserve on decision-making in daily clinical practice: A single center experience in Egypt.

BACKGROUND: Fractional flow reserve (FFR) is the reference standard for the assessment of the functional significance of coronary artery stenoses, but remains underutilized. Our aims were to study whether FFR changed the decision for treatment of intermediate coronary lesions and to assess the clinical outcome in the deferred and intervention groups. METHODS: In this retrospective study, coronary angiograms of patients with moderately stenotic lesions (40-70%) for which FFR was performed were re-analyzed by three experienced interventional cardiologists (blinded to FFR results) to determine its angiographic significance and whether to defer or perform an intervention. RESULTS: We revised 156 equivocal lesions of 151 patients. The clinical presentation were stable angina (65.6%) and acute coronary syndrome in (34.4%). All reviewers had concordant agreement to do PCI in 59 (37.8%) lesions based on angiographic assessment. Interestingly 23 (39%) of these lesions were functionally non-significant by FFR. The reviewers agreed to defer 97 (62.2%) lesions, however, 32 (33%) of these lesions were functionally significant by FFR and necessitated PCI. MACE were similar in both groups (1.5% vs 2.4%, p = 1.0). CONCLUSION: Mismatches between visually- and FFR- estimated significance of intermediate coronary stenosis are frequently encountered across a wide spectrum of clinical presentations. FFR leads to a change in decision for coronary intervention. The clinical and cost implications of such changes-in areas with limited resources- needs further evaluation.

Validation of Noninvasive Measurement of Cardiac Output Using Inert Gas Rebreathing in a Cohort of Patients With Heart Failure and Reduced Ejection Fraction.

BACKGROUND: Cardiac output (CO) is a key indicator of cardiac function in patients with heart failure. No completely accurate method is available for measuring CO in all patients. The objective of this study was to validate CO measurement using the inert gas rebreathing (IGR) method against other noninvasive and invasive methods of CO quantification in a cohort of patients with heart failure and reduced ejection fraction. METHODS AND RESULTS: The study included 97 patients with heart failure and reduced ejection fraction (age 42±15.5 years; 64 patients (65.9%) had idiopathic dilated cardiomyopathy and 21 patients (21.6%) had ischemic heart disease). Median left ventricle ejection fraction was 24% (10%-36%). Patients with atrial fibrillation were excluded. CO was measured using 4 methods (IGR, cardiac magnetic resonance imaging, cardiac catheterization, and echocardiography) and indexed to body surface area (cardiac index [CI]). All studies were performed within 48 hours. Median CI measured by IGR was 1.75, by cardiac magnetic resonance imaging was 1.82, by cardiac catheterization was 1.65, and by echo was 1.7 L·min-1·m-2. There were significant modest linear correlations between IGR-derived CI and cardiac magnetic resonance imaging-derived CI (r=0.7; P<0.001), as well as cardiac catheterization-derived CI (r=0.6; P<0.001). Using Bland-Altman analysis, the agreement between the IGR method and the other methods was as good as the agreement between any 2 other methods with each other. CONCLUSIONS: The IGR method is a simple, accurate, and reproducible noninvasive method for quantification of CO in patients with advanced heart failure. The prognostic value of this simple measurement needs to be studied prospectively.