The involvement of serotonin in the formation of thrombi at critical coronary arterial stenoses in humans

Animal experiments show a role for serotonin in mediating coronary arterial thrombosis. To test whether this might also be the case in humans, 61 patients with critical coronary artery stenoses shown by coronary angiography were divided into thromboxane-inhibition (30 treated with aspirin) and serotonin-antagonist (31, with ketanserin) groups. They were examined for coronary occlusion until they underwent coronary artery bypass grafting or angioplasty. During this waiting period, 7 of the subjects in the thromboxane-inhibition group had coronary arterial occlusions, and 4 of the 7 died. One occlusion occurred in the serotonin-antagonism group. The probability of the occlusion rate in subjects subjected to thromboxane inhibition and those recieving a serotonin antagonist being the same was less than 0.0245, as measured by Fisher's exact test. The probability of survival from myocardial infarction being the same for the two groups was less than 0.05, as measured by the Mantel-Haentzel test. These results might permit rejection of the null hypothesis for one favoring greater effectiveness of serotonin antagonism, but this conclusion would depend on the two methods adopted. We have therefore adopted the null hypothesis and have concluded that serotonin may be as important in mediating coronary thrombosis in humans as it is in animals.