Browsing by Author "Cardim, N"
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- Cost-Effectiveness of Different Diagnostic Strategies in Suspected Stable Coronary Artery Disease in PortugalPublication . Ferreira, AM; Marques, H; Araújo Gonçalves, P; Cardim, NBACKGROUND: Cost-effectiveness is an increasingly important factor in the choice of a test or therapy. OBJECTIVE: To assess the cost-effectiveness of various methods routinely used for the diagnosis of stable coronary disease in Portugal. METHODS: Seven diagnostic strategies were assessed. The cost-effectiveness of each strategy was defined as the cost per correct diagnosis (inclusion or exclusion of obstructive coronary artery disease) in a symptomatic patient. The cost and effectiveness of each method were assessed using Bayesian inference and decision-making tree analyses, with the pretest likelihood of disease ranging from 10% to 90%. RESULTS: The cost-effectiveness of diagnostic strategies was strongly dependent on the pretest likelihood of disease. In patients with a pretest likelihood of disease of ≤50%, the diagnostic algorithms, which include cardiac computed tomography angiography, were the most cost-effective. In these patients, depending on the pretest likelihood of disease and the willingness to pay for an additional correct diagnosis, computed tomography angiography may be used as a frontline test or reserved for patients with positive/inconclusive ergometric test results or a calcium score of >0. In patients with a pretest likelihood of disease of ≥ 60%, up-front invasive coronary angiography appears to be the most cost-effective strategy. CONCLUSIONS: Diagnostic algorithms that include cardiac computed tomography angiography are the most cost-effective in symptomatic patients with suspected stable coronary artery disease and a pretest likelihood of disease of ≤50%. In high-risk patients (pretest likelihood of disease ≥ 60%), up-front invasive coronary angiography appears to be the most cost-effective strategy. In all pretest likelihoods of disease, strategies based on ischemia appear to be more expensive and less effective compared with those based on anatomical tests.
- Intracoronary Delivery of Human Mesenchymal/Stromal Stem Cells: Insights from Coronary Microcirculation Invasive Assessment in a Swine ModelPublication . Fiarresga, A; Mata, M; Cavaco-Gonçalves, S; Selas, M; Simões, I; Oliveira, E; Carrapiço, B; Cardim, N; Cabral, J; Cruz Ferreira, R; Silva, CBACKGROUND: Mesenchymal stem/stromal cells have unique properties favorable to their use in clinical practice and have been studied for cardiac repair. However, these cells are larger than coronary microvessels and there is controversy about the risk of embolization and microinfarctions, which could jeopardize the safety and efficacy of intracoronary route for their delivery. The index of microcirculatory resistance (IMR) is an invasive method for quantitatively assessing the coronary microcirculation status. OBJECTIVES: To examine heart microcirculation after intracoronary injection of mesenchymal stem/stromal cells with the index of microcirculatory resistance. METHODS: Healthy swine were randomized to receive by intracoronary route either 30x106 MSC or the same solution with no cells (1% human albumin/PBS) (placebo). Blinded operators took coronary pressure and flow measurements, prior to intracoronary infusion and at 5 and 30 minutes post-delivery. Coronary flow reserve (CFR) and the IMR were compared between groups. RESULTS: CFR and IMR were done with a variance within the 3 transit time measurements of 6% at rest and 11% at maximal hyperemia. After intracoronary infusion there were no significant differences in CFR. The IMR was significantly higher in MSC-injected animals (at 30 minutes, 14.2U vs. 8.8U, p = 0.02) and intragroup analysis showed a significant increase of 112% from baseline to 30 minutes after cell infusion, although no electrocardiographic changes or clinical deterioration were noted. CONCLUSION: Overall, this study provides definitive evidence of microcirculatory disruption upon intracoronary administration of mesenchymal stem/stromal cells, in a large animal model closely resembling human cardiac physiology, function and anatomy.
- Invasive Assessment of the Coronary Microcirculation Using the Index of Microcirculatory Resistance: Description and Validation of an Animal ModelPublication . Fiarresga, A; Selas, M; Oliveira, E; Cavaco-Gonçalves, S; Cacela, D; Carrapiço, B; Cardim, N; Cruz Ferreira, RINTRODUCTION: The index of microcirculatory resistance (IMR) enables/provides quantitative, invasive, and real-time assessment of coronary microcirculation status. AIMS: The primary aim of this study was to validate the assessment of IMR in a large animal model, and the secondary aim was to compare two doses of intracoronary papaverine, 5 and 10 mg, for induction of maximal hyperemia and its evolution over time. METHODS: Measurements of IMR were performed in eight pigs. Mean distal pressure (Pd) and mean transit time (Tmn) were measured at rest and at maximal hyperemia induced with intracoronary papaverine, 5 and 10 mg, and after 2, 5, 8 and 10 minutes. Disruption of the microcirculation was achieved by selective injection of 40-μm microspheres via a microcatheter in the left anterior descending artery. RESULTS: In each animal 14 IMR measurements were made. There were no differences between the two doses of papaverine regarding Pd response and IMR values - 11 ± 4.5 U with 5 mg and 10.6 ± 3 U with 10 mg (p=0.612). The evolution of IMR over time was also similar with the two doses, with significant differences from resting values disappearing after five minutes of intracoronary papaverine administration. IMR increased with disrupted microcirculation in all animals (41 ± 16 U, p=0.001). CONCLUSIONS: IMR provides invasive and real-time assessment of coronary microcirculation. Disruption of the microvascular bed is associated with a significant increase in IMR. A 5-mg dose of intracoronary papaverine is as effective as a 10-mg dose in inducing maximal hyperemia. After five minutes of papaverine administration there is no significant difference from resting hemodynamic status.