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Minten L, Bennett J, McCutcheon K, Oosterlinck W, Algoet M, Otsuki H, Takahashi K, Fearon WF, Dubois C. Optimization of Absolute Coronary Blood Flow Measurements to Assess Microvascular Function: In Vivo Validation of Hyperemia and Higher Infusion Speeds. Circ Cardiovasc Interv 2024; 17:e013860. [PMID: 38682331 DOI: 10.1161/circinterventions.123.013860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 03/15/2024] [Indexed: 05/01/2024]
Abstract
BACKGROUND Reliable assessment of coronary microvascular function is essential. Techniques to measure absolute coronary blood flow are promising but need validation. The objectives of this study were: first, to validate the potential of saline infusion to generate maximum hyperemia in vivo. Second, to validate absolute coronary blood flow measured with continuous coronary thermodilution at high (40-50 mL/min) infusion speeds and asses its safety. METHODS Fourteen closed-chest sheep underwent absolute coronary blood flow measurements with increasing saline infusion speeds at different dosages under general anesthesia. An additional 7 open-chest sheep underwent these measurements with epicardial Doppler flow probes. Coronary flows were compared with reactive hyperemia after 45 s of coronary occlusion. RESULTS Twenty milliliters per minute of saline infusion induced a significantly lower hyperemic coronary flow (140 versus 191 mL/min; P=0.0165), lower coronary flow reserve (1.82 versus 3.21; P≤0.0001), and higher coronary resistance (655 versus 422 woods units; P=0.0053) than coronary occlusion. On the other hand, 30 mL/min of saline infusion resulted in hyperemic coronary flow (196 versus 192 mL/min; P=0.8292), coronary flow reserve (2.77 versus 3.21; P=0.1107), and coronary resistance (415 versus 422 woods units; P=0.9181) that were not different from coronary occlusion. Hyperemic coronary flow was 40.7% with 5 mL/min, 40.8% with 10 mL/min, 73.1% with 20 mL/min, 102.3% with 30 mL/min, 99.0% with 40 mL/min, and 98.0% with 50 mL/min of saline infusion when compared with postocclusive hyperemic flow. There was a significant bias toward flow overestimation (Bland-Altman: bias±SD, -73.09±30.52; 95% limits of agreement, -132.9 to -13.27) with 40 to 50 mL/min of saline. Occasionally, ischemic changes resulted in ventricular fibrillation (9.5% with 50 mL/min) at higher infusion rates. CONCLUSIONS Continuous saline infusion of 30 mL/min but not 20 mL/min induced maximal hyperemia. Absolute coronary blood flow measured with saline infusion speeds of 40 to 50 mL/min was not accurate and not safe.
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Affiliation(s)
- Lennert Minten
- Department of Cardiovascular Sciences, Katholieke Universiteit Leuven, Belgium (L.M., J.B., K.M.C., W.O., M.A., C.D.)
- Division of Cardiovascular Medicine, Stanford University, CA (L.M., H.O., K.T., W.F.F.)
| | - Johan Bennett
- Department of Cardiovascular Sciences, Katholieke Universiteit Leuven, Belgium (L.M., J.B., K.M.C., W.O., M.A., C.D.)
- Departments of Cardiovascular Medicine (J.B., C.D.), UZ Leuven, Belgium
| | - Keir McCutcheon
- Department of Cardiovascular Sciences, Katholieke Universiteit Leuven, Belgium (L.M., J.B., K.M.C., W.O., M.A., C.D.)
| | - Wouter Oosterlinck
- Department of Cardiovascular Sciences, Katholieke Universiteit Leuven, Belgium (L.M., J.B., K.M.C., W.O., M.A., C.D.)
- Cardiac Surgery (W.O., M.A.), UZ Leuven, Belgium
| | - Michiel Algoet
- Department of Cardiovascular Sciences, Katholieke Universiteit Leuven, Belgium (L.M., J.B., K.M.C., W.O., M.A., C.D.)
- Cardiac Surgery (W.O., M.A.), UZ Leuven, Belgium
| | - Hisao Otsuki
- Division of Cardiovascular Medicine, Stanford University, CA (L.M., H.O., K.T., W.F.F.)
| | - Kuniaki Takahashi
- Division of Cardiovascular Medicine, Stanford University, CA (L.M., H.O., K.T., W.F.F.)
| | - William F Fearon
- Division of Cardiovascular Medicine, Stanford University, CA (L.M., H.O., K.T., W.F.F.)
- VA Palo Alto Health Care System, CA (W.F.F.)
| | - Christophe Dubois
- Department of Cardiovascular Sciences, Katholieke Universiteit Leuven, Belgium (L.M., J.B., K.M.C., W.O., M.A., C.D.)
- Departments of Cardiovascular Medicine (J.B., C.D.), UZ Leuven, Belgium
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Minten L, Bennett J, Otsuki H, Takahashi K, Fearon WF, Dubois C. Differential Effect of Aortic Valve Replacement for Severe Aortic Stenosis on Hyperemic and Resting Epicardial Coronary Pressure Indices. J Am Heart Assoc 2024; 13:e034401. [PMID: 38761080 PMCID: PMC11179829 DOI: 10.1161/jaha.124.034401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/23/2024] [Indexed: 05/20/2024]
Abstract
BACKGROUND Coronary pressure indices to assess coronary artery disease are currently underused in patients with aortic stenosis due to many potential physiological effects that might hinder their interpretation. Studies with varying sample sizes have provided us with conflicting results on the effect of transcatheter aortic valve replacement (TAVR) on these indices. The aim of this meta-analysis was to study immediate and long-term effects of TAVR on fractional flow reserve (FFR) and nonhyperemic pressure ratios (NHPRs). METHODS AND RESULTS Lesion-specific coronary pressure data were extracted from 6 studies, resulting in 147 lesions for immediate change in FFR analysis and 105 for NHPR analysis. To investigate the long-term changes, 93 lesions for FFR analysis and 68 for NHPR analysis were found. Lesion data were pooled and compared with paired t tests. Immediately after TAVR, FFR decreased significantly (-0.0130±0.0406 SD, P: 0.0002) while NHPR remained stable (0.0003±0.0675, P: 0.9675). Long-term after TAVR, FFR decreased significantly (-0.0230±0.0747, P: 0.0038) while NHPR increased nonsignificantly (0.0166±0.0699, P: 0.0543). When only borderline NHPR lesions were considered, this increase became significant (0.0249±0.0441, P: 0.0015). Sensitivity analysis confirmed our results in borderline lesions. CONCLUSIONS TAVR resulted in small significant, but opposite, changes in FFR and NHPR. Using the standard cut-offs in patients with severe aortic stenosis, FFR might underestimate the physiological significance of a coronary lesion while NHPRs might overestimate its significance. The described changes only play a clinically relevant role in borderline lesions. Therefore, even in patients with aortic stenosis, an overtly positive or negative physiological assessment can be trusted.
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Affiliation(s)
- Lennert Minten
- Department of Cardiovascular Sciences Katholieke Universiteit Leuven Leuven Belgium
- Division of Cardiovascular Medicine Stanford University Palo Alto CA
| | - Johan Bennett
- Department of Cardiovascular Sciences Katholieke Universiteit Leuven Leuven Belgium
- Department of Cardiovascular Medicine University Hospitals Leuven (UZ Leuven) Leuven Belgium
| | - Hisao Otsuki
- Division of Cardiovascular Medicine Stanford University Palo Alto CA
| | - Kuniaki Takahashi
- Division of Cardiovascular Medicine Stanford University Palo Alto CA
| | - William F Fearon
- Division of Cardiovascular Medicine Stanford University Palo Alto CA
| | - Christophe Dubois
- Department of Cardiovascular Sciences Katholieke Universiteit Leuven Leuven Belgium
- Department of Cardiovascular Medicine University Hospitals Leuven (UZ Leuven) Leuven Belgium
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