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- Sun, Y, et al.
(författare)
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Estimation of volume flow rate by surface integration of velocity vectors from color Doppler images.
- 1995
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795 .- 0735-1097 .- 1558-3597. ; 8:6, s. 904-914
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Tidskriftsartikel (refereegranskat)abstract
- A new Doppler echocardiographically based method has been developed to quantify volume flow rate by surface integration of velocity vectors (SIVV). Electrocardiographic-gated color Doppler images acquired in two orthogonal planes were used to estimate volume flow rate through a bowl-shaped surface at a given time and distance from the probe. To provide in vitro validation, the method was tested in a hydraulic model representing a pulsatile flow system with a restrictive orifice. Accurate estimates of stroke volume (+/- 10%) were obtained in a window between 1.2 and 1.6 cm proximal to the orifice, just before the region of prestenotic acceleration. By use of the Bernoulli's equation, the estimated flows were used to generate pressure gradient waveforms across the orifice, which agreed well with the measured flows. To demonstrate in vivo applicability, the SIVV method was applied retrospectively to the determination of stroke volume and subaortic flow from the apical three-chamber and five-chamber views in two patients. Stroke volume estimates along the left ventricular outflow tract showed a characteristic similar to that in the in vitro study and agreed well with those obtained by the Fick oxygen method. The region where accurate measurements can be obtained is affected by instrumental factors including Nyquist velocity limit, wall motion filter cutoff, and color flow sector angle. The SIVV principle should be useful for quantitative assessment of the severity of valvular abnormalities and noninvasive measurement of pulsatile volume flows in general.
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- Frostfeldt, Gunnar, et al.
(författare)
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Low molecular weight heparin (Dalteparin) as adjuvant treatment to thrombolysis in acute myocardial infarction-a pilot study : BIOchemical markers in acute coronary syndromes (BIOMACS II)
- 1999
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Ingår i: Journal of the American College of Cardiology. - 0735-1097 .- 1558-3597. ; 33:3, s. 627-633
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: This randomized, double blind, placebo-controlled pilot trial evaluated the effect of dalteparin as an adjuvant to thrombolysis in patients with acute myocardial infarction regarding early reperfusion, recurrent ischemia and patency at 24 h. BACKGROUND: Low-molecular-weight heparin, given subcutaneously twice daily without monitoring, might be an attractive alternative to conventional intravenous heparin in the treatment of acute myocardial infarction. METHODS: In 101 patients dalteparin/placebo 100 IU/kg was given just before streptokinase and a second injection 120 IU/kg after 12 h. Monitoring with continuous vector-ECG was done to obtain signs of early reperfusion and later ischemic episodes. Blood samples for myoglobin were obtained at start and after 90 min to evaluate signs of reperfusion. Coronary angiography was performed after 20-28 h to evaluate TIMI-flow in the infarct-related artery. RESULTS: Dalteparin added to streptokinase tended to provide a higher rate of TIMI grade 3 flow in infarct-related artery compared to placebo, 68% versus 51% (p = 0.10). Dalteparin had no effects on noninvasive signs of early reperfusion. In patients with signs of early reperfusion, there seemed to be a higher rate of TIMI grade 3 flow, 74% versus 46% (myoglobin) (p = 0.04) and 73% versus 52% (vector-ECG) (p = 0.11). Ischemic episodes 6-24 h. after start of treatment were fewer in the dalteparin group, 16% versus 38% (p = 0.04). CONCLUSIONS: When dalteparin was added as an adjuvant to streptokinase and aspirin, there were tendencies for less ECG monitoring evidence of recurrent ischemia and better patency at 24 h, warranting further study.
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| 10. |
- Goel, Kashish, et al.
(författare)
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Novel Cyp2C19 Genetic Variants associated with Stent Thrombosis : a Next Generation Sequencing Study
- 2018
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Ingår i: Journal of the American College of Cardiology. - : ELSEVIER SCIENCE INC. - 0735-1097 .- 1558-3597. ; 71:11, s. 1205-1205
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundCommonly tested Loss-of-function (LOF) alleles in CYP2C19 are present in 30-40% of patients who experience stent thrombosis. The objective of this study was to identify novel genetic variants in CYP2C19 gene associated with stent thrombosis.MethodsWe included 70 patients with definite stent thrombosis while on clopidogrel who had stored DNA samples in our institutional (n=12) or PLATO trial (n=70) biorepository. Cases were matched 1:1 with controls for age, race, sex, diabetes, type of stent, and presentation. All controls were on clopidogrel and free of recurrent events. Clinical Pharmacogenetics (PGx) Implementation Consortium (CPIC) guidelines were used to determine the list of known PGx variants and dbSNP version 142 was used to assess novel variants. Whole exome sequencing was performed using the protocol for Agilent's SureSelect Human All Exon v5 + UTRs 75 MB kit and additional custom primers were designed to cover the entire CYP2C19 gene.ResultsMean age was 63 ± 12 years, and 71% were male. We identified a total of 456 single nucleotide variants (SNV) in the CYP2C19 gene (cases: 376; controls: 288), of which 5 were synonymous, 6 non-synonymous, 46 indels and 449 intronic SNVs. There were 168 vs. 80 novel CYP2C19 variants and 10 vs. 5 indels in cases vs. controls, respectively. Four SNVs (3 missense and 1 synonymous) were present only in cases, whereas 3 SNVs (1 misssense, 1 synonymous and 1 intron) were unique to controls. There were no detectable differences in the frequency of LOF CYP2C19*2 allele (cases 34% vs. controls 31%) or other CPIC annotated PGx variants in cases and controls. After excluding the known PGx variants, there were 10 indels (all intronic) out of which 7 were novel in cases and were not present in controls.ConclusionWe describe several novel genetic variants in the CYP2C19 gene in patients treated with clopidogrel after coronary stenting. We identified 168 novel SNVs and 10 novel indels in the CYP2C19 gene of patients with stent thrombosis. Four SNVs and 9 indels were unique to cases. Functional validation of these CYP2C19 genetic variants may provide important insights of CYP2C19 and the pathophysiology of stent thrombosis in clopidogrel treated patients.
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