Coronary collateral quantitation in patients with coronary artery disease using intravascular flow velocity or pressure measurements

{ "0" : "Department of Cardiology, University Hospital, Bern, Switzerland" , "2" : "CAD, coronary artery disease" , "3" : "CFVR, coronary flow velocity reserve" , "4" : "CVP, central venous pressure" , "5" : "IC, intracoronary" , "6" : "PTCA, percutaneous transluminal coronary angioplasty"}
Journal of the American College of Cardiology (Impact Factor: 14.09). 11/1998; DOI: 10.1016/S0735-1097(98)00384-2

ABSTRACT Objectives. This study evaluated two methods for the quantitative measurement of collaterals using intracoronary (IC) blood flow velocity or pressure measurements.Background. The extent of myocardial necrosis after coronary artery occlusion is substantially influenced by the collateral circulation. So far, qualitative methods have been available to assess the human coronary collateral circulation, thus restraining the conclusive investigation of, for example, therapies to promote collateral development.Methods. Fifty-one patients with a coronary artery stenosis to be treated by percutaneous transluminal coronary angioplasty (PTCA) were investigated using IC PTCA guidewire-based Doppler and pressure sensors positioned distal to the stenosis. Simultaneous measurements of aortic pressure, IC velocity and pressure distal to the stenosis during and after PTCA provided the variables for calculating collateral flow indices (CFIv and CFIp) that express collateral flow as a fraction of flow via the patent vessel. Both CFIv and CFIp were compared with conventional methods for collateral assessment, among them ST-segment changes >1 mm on IC and surface electrocardiogram (ECG) at PTCA. Also, CFIv and CFIp were compared with each other.Results. In 11 patients without ECG signs of ischemia during PTCA (sufficient collaterals), relative collateral flow amounted to 46% as determined by Doppler and pressure wire. Patients with insufficient collaterals (n = 40) had relative collateral flow values of 18%. Using a threshold of CFI = 30%, sufficient and insufficient collaterals could be diagnosed with 100% sensitivity and 93% specificity by IC Doppler, and 75% sensitivity and 92% specificity by IC pressure measurements. The agreement between Doppler and pressure measurements was good: CFIv = 0.08 + 0.8 CFIp, r = 0.80, p = 0.0001.Conclusions. Intracoronary flow velocity or pressure measurements during routine PTCA represent an accurate and, at last, quantitative method for assessing the coronary collateral circulation in humans.

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    ABSTRACT: Coronary collaterals are present at birth, with wide interindividual variation in their functional capacity. These vessels protect jeopardized myocardium, and the number of collaterals and the extent of their coverage are associated with improved survival in patients with coronary heart disease. The collateral circulation is not a permanent set of structures, but undergoes dynamic changes with important consequences for cardioprotection. If a severe atherosclerotic lesion develops in an artery supplying tissue downstream of a total occlusion through collateral blood flow, pressure gradients across the collateral bed change. The result is that some of the collateral flow previously supplying the perfusion territory of the totally occluded artery is redirected to the perfusion territory of the donor artery, thus producing a 'collateral steal'. The collateral circulation can regress once antegrade flow in the main dependent artery is re-established, as occurs following the recanalization of a chronic total occlusion. The clinical benefits of coronary revascularization must be cautiously weighed against the risk of reducing the protective support derived from coronary collaterals. Consequently, pharmacological, gene-based, and cell-based therapeutic attempts have been made to enhance collateral function. Although such approaches have so far yielded no, or modest, beneficial results, the rapidly accruing data on coronary collateral circulation will hopefully lead to new effective therapeutic strategies.
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