Intracoronary papaverine: an ideal coronary vasodilator for studies of the coronary circulation in conscious humans.

Abstract

An ideal coronary vasodilator for studying coronary flow reserve in humans would rapidly produce maximal coronary vasodilation, be short acting to permit repeated measurements, and not alter systemic hemodynamics. The two commonly used vasodilators (dipyridamole and meglumine diatrizoate) do not satisfy these criteria; meglumine diatrizoate does not produce maximal hyperemia and dipyridamole has a long duration of effect (greater than 30 min). In this study we used a subselective coronary Doppler catheter to measure the dose-response kinetics of a shorter acting vasodilator, intracoronary papaverine. In 10 patients with normal coronary vessels, the maximal vasodilator response to papaverine was compared with that to intravenous dipyridamole (0.56 mg/kg infused over 4 min) and intracoronary meglumine diatrizoate. The increase in coronary blood flow velocity after the maximal dose of papaverine (4.8 ± 0.4 peak/resting velocity ratio, mean ± SEM) was nearly identical to that seen after infusion of dipyridamole (4.8 + 0.6) and was significantly greater than that after meglumine diatrizoate (3.1 ± 0.2, p < .01). At maximal hyperemia, mean arterial blood pressure fell 9 + 2% (mean + SEM) after intracoronary papaverine, 8 + 4% after dipyridamole, and 3 + 3% after meglumine diatrizoate. The dose-response kinetics of intracoronary papaverine were studied in 13 patients with normal coronary arteries. In the left coronary artery, maximal vasodilation (5.4 ± 0.6) was achieved with 8 mg in six of eight patients and with 12 mg in all patients. In the right coronary artery, maximal vasodilation (4.8 ± 0.7) was achieved with 6 mg in four or five patients and with 8 mg in all patients. Onset of maximal vasodilation was rapid after papaverine (16 + 1 sec) and meglumine diatrizoate (15 ± 1), but prolonged after dipyridamole (4.8 ± 0.4 min after onset of infusion). The duration of maximal vasodilation was brief after papaverine (49 + 10 sec) and meglumine diatrizoate (8 ± 1 sec), but prolonged after dipyridamole (greater than 4 min). Coronary blood flow velocity returned to within 10% of resting values quickly after papaverine (128 ± 15 sec) and meglumine diatrizoate (42 ± 4 sec). After dipyridamole infusion, however, coronary blood flow velocity remained elevated for greater than 4 min after completion of infusion. These results suggest that papaverine can produce intense, rapid-acting vasodilation of the coronary arteriolar bed equivalent to that stimulated by intravenous dipyridamole without markedly altering systemic arterial pressure. Although the extent and duration of vasodilation was dose dependent, the hyperemic period in all patients was sufficiently brief to allow multiple measurements of coronary reserve over a short period of time. The use of intracoronary papaverine to measure the maximal flow reserve capacity of individual coronary vessels should greatly facilitate studies of the coronary circulation in patients undergoing cardiac catheterization

Coronary artery constriction caused by the cold pressor test in human hypertension.

“…20 The coronary flow reserve was normal in all control subjects and in eight HTN patients and was slightly reduced in two HTN patients. However, the mean value of coronary flow reserve was significantly lower in HTN patients than in normotensive subjects (P<.05) (Table).…”

“…Coronary flow reserve was calculated as the ratio of peak blood flow velocity (maximal kilohertz shift after papaverine) to resting blood flow velocity (average of two successive measures, the second of which was performed after return to baseline coronary flow velocity). 20 …”

Does the quantitative assessment of coronary artery dimensions predict the physiologic significance of a coronary stenosis?

“…Hyperosmolar ionic contrast media do not produce maximal vasodilation. 10 The exact dose of intracoronary papaverine that is needed to induce maximal coronary vasodilation has recently been established. Wilson and White'0 compared the coronary hyperemic response after 4, 8, 12, and 16 mg intracoronary papaverine and reported a maximal hyperemic response after 8 or 12 mg in all coronary arteries.…”

Assessment of Left Internal Mammary Artery Graft Patency by Transthoracic Doppler Echocardiography

“…Invasive studies have shown that when maximal coronary dilatation is induced, blood flow or blood flow velocity increases more in normal vessels than in those affected by significant stenosis. [17][18][19] Measurement of blood flow after the use of coronary vasodilators would allow noninvasive assessment of flow reserve in the LIMA and may be useful in the assessment of graft stenoses of moderate severity. This technique has been reported in the assessment of LAD stenoses using transesophageal echocardiography.…”