The mechanism of hypotension following angiography.
The hypotension observed following the intracardiac injection of contrast media is believed to be the result of myocardial depression, peripheral vasodilatation, or both. It is unclear which of these factors is primarily involved in different types of angiography. To assess this problem, Renografin-76 was injected into the aortic root of 15 anesthetized dogs (1 ml/kg) and into the left coronary artery (3-5 ml) in 18 dogs. The heart rate, the systolic and diastolic arterial pressures, left ventricular pressure, peak dp/dt and dp/dt-40 were monitored continuously until return to baseline. Following selective left coronary artery injection, both systolic and diastolic pressures decreased maximally at 5 seconds with parallel changes in peak dp/dt and dp/dt-40. Following the aortic root injection, the blood pressure response was biphasic, increasing at 5 seconds and decreasing maximally at 20 seconds. The corresponding changes in peak dp/dt and dp/dt-40 were initial depression at 5 seconds with quick return to baseline and increase above control at the time of maximal hypotension. The left ventricular end diastolic pressure rose maximally at 5 to 10 seconds for both coronary and aortic injections. The mechanism of hypotension, therefore, varies with the type of angiography. Myocardial depression appears to be a primary factor with selective coronary angiography. However, with aortic root injection, myocardial contractility, although initially depressed, is already improved at the time of maximal hypotension, and thus peripheral vasocilatation is probably the prime mechanism of the hypotension.
D000790:Angiocardiography / Q000009:adverse effects*; D000818:Animals; D003287:Contrast Media / Q000009:adverse effects*; D003973:Diatrizoate / Q000009:adverse effects; D003974:Diatrizoate Meglumine / Q000009:adverse effects; D004285:Dogs; D007022:Hypotension / Q000209:etiology*
D003287:Contrast Media; D003973:Diatrizoate; D003974:Diatrizoate Meglumine