Simultaneous intracoronary velocity- and pressure-derived assessment of adenosine-induced collateral hemodynamics in patients with one- to two-vessel coronary artery disease

Abstract

Overall, patients with well, versus poorly developed coronary collaterals do better regarding the capacity to increase collateral flow in response to adenosine. In patients with good, but not poor, collaterals, an adenosine-induced collateral flow increase depends on the ipsilateral distal vascular resistance decrease, but is also directly influenced by the severity of a contralateral stenosis and probably by the size of the collateralized vascular bed.

Direct Assessment of Coronary Steal and Associated Changes of Collateral Hemodynamics in Chronic Total Coronary Occlusions

“…14,16 They reported an increase of collateral flow, but a few patients also showed a decrease, ie, coronary steal. Another study assessed Doppler coronary flow velocity during intracoronary adenosine injection into the collateral-dependent artery; coronary steal occurred in 10% of patients.…”

“…14,24 Another issue that limits the comparability with previous studies is that coronary steal was not always defined as a reduction of flow velocity 14,24 but as a drop of a pressurederived collateral flow index. 16 But because steal represents a reduction of flow, and distal coronary pressure (P D ) may decrease even when flow increases during adenosine infusion (Figure 4), coronary steal should be defined by parameters of flow and not pressure.…”

“…All 3 assumptions are supported by our data. First, coronary steal required well-developed collaterals, 14,16,24 whereas collaterals in group N had a lower CFI, higher R CP , and predominantly a systolic collateral flow pattern, as evidence of reduced collateral function. 18,26 As shown previously, collateral resistance is not negligible.…”

“…A peripheral resistance index was calculated as R P ϭP D /APV (mm Hg · cm Ϫ1 · s Ϫ1 ). 14,16 The resistance index of the collateral supply pathway was defined as R CP ϭ(P Ao ϪP D )/APV (mm Hg · cm Ϫ1 · s Ϫ1 ), incorporating both the resistance of the collateral vessel and of the donor segment proximal to the collateral takeoff ( Figure 1). …”

“…18,26 As shown previously, collateral resistance is not negligible. 14,16,18 The assumption that large collaterals, because of a low resistance, would not show steal 25 was confirmed by our study, because large collaterals were only observed in group R but not in group S. The lack of a vasodilatory reserve is demonstrated by the unchanged R P in group S, whereas it was decreased significantly in group R. On the other hand, the higher R P in group N and its lack of response to adenosine could be related to the higher proportion of diabetics with a known prevalence of microvascular dysfunction. 27 We did not record directly the coronary pressure in the donor artery at the collateral origin.…”