Intracoronary propylene glycol

Intracoronary-administered urapidil does not influence myocardial contractility, metabolic activity, or coronary sinus blood flow in humans

OBJECTIVE

To compare the acute effect of intracoronary administration of urapidil and saline on myocardial contractility and metabolic activity.

DESIGN

Prospective, controlled, open-label study.

SETTING

University teaching hospital.

PARTICIPANTS AND INTERVENTIONS

Eight patients with stable coronary artery disease (CAD) undergoing elective percutaneous transluminal coronary angioplasty (PTCA) received normal saline followed by urapidil, 4 mg, injected directly into the left main coronary artery.

MEASUREMENTS AND MAIN RESULTS

Because local intracoronary administration is a non-steady-state condition, an in vitro model was used before the clinical experiments to establish the kinetic effects of acute administration of urapidil. The clinical experiments were performed in eight patients with CAD after PTCA. Measurements included a complete hemodynamic profile, coronary sinus blood flow (continuous thermodilution), left ventricular (LV) peak (+) dP/dt, LV peak (-) dP/dt, LV dP/dt/P(D)40, and LV end-diastolic pressures. Arterial and coronary venous blood samples were also obtained for the calculation of myocardial oxygen consumption. Baseline measurements I were first obtained, followed by intracoronary injection of 2 mL of saline. Additional measurements were obtained 1, 5, and 10 minutes after administration of saline. After a resting period (15 minutes), baseline measurements II, and intracoronary injection of urapidil, 4 mg (dissolved in 2 mL saline), additional measurements were obtained 1, 5, and 10 minutes later. Heart rate decreased 2.7+/-3.5 beats/min after injection of saline, whereas heart rate increased 2.0+/-1.8 beats/min after intracoronary urapidil, resulting in a significant difference in treatment effect (p = 0.003). There were no additional differences in treatment effect for any of the other measured or calculated parameters reflecting systemic hemodynamics, LV contractility, coronary dynamics, and myocardial metabolic activity.

CONCLUSION

The results suggest that intracoronary bolus administration of preservative-free urapidil, 4 mg, is not associated with any detectable effect on myocardial contractility or coronary smooth muscle in awake nonsurgical patients with CAD, after PTCA.

Propylene glycol-induced proximal renal tubular cell injury

Propylene glycol is a solvent that is used in many oral, injectable, and topical medications. Although uncommon, acute renal failure has been attributed to propylene glycol. The mechanism of propylene glycol-mediated renal injury is unknown. We report a case of acute renal failure in a 16-year-old boy given large doses of pentobarbital and phenobarbital, both of which are solubilized with propylene glycol. A renal biopsy showed proximal renal tubular cell swelling and vacuole formation. The data from this case suggest that the reversible acute renal failure caused by propylene glycol is attributable to proximal renal tubular cell injury.