Sudden paradoxic clinical deterioration during angioplasty of the occluded right coronary artery in acute myocardial infarction

Abstract

The beneficial versus detrimental effects of emergency coronary angioplasty for achieving myocardial reperfusion remain controversial. We studied 83 consecutive patients treated with angioplasty of occluded (Thrombolysis in Myocardial Infarction trial [TIMID grade 0 or 1 flow) infarct-related arteries. Seventy patients had unsuccessful intravenous thrombolytic therapy and subsequently had rescue angioplasty and 13 patients had direct angioplasty without prior thrombolytic therapy. Forty-six patients had occlusion of the right coronary artery and 37 of the left anterior descending coronary artery. These two patient groups were similar with respect to age, percent of men, history of prior myocardial infarction, known cardiac risk factors and elapsed time from onset of chest pain to reperfusion. Angioplasty was initially successful in achieving TIMI grade 2 or 3 flow in 87% of right coronary artery occlusions and 92% of left anterior descending artery occlusions (p = 0.47). At 1 week follow-up catheterization, vessel patency was 63% for right coronary and 85% for left anterior descending infarct-related arteries (p = 0.03). Patients with right coronary artery occlusion had a higher incidence of life-threatening complications during angioplasty than did patients with left anterior descending artery occlusion (p = 0.002) including, respectively: 1) the need for cardiopulmonary resuscitation in 16% versus 0% (p = 0.02), 2) sustained ventricular tachycardia or ventricular fibrillation requiring electric cardioversion in 9% versus 3% (p = 0.33), and 3) sustained hypotension requiring inotropic agents or balloon pump therapy in 11% versus 3% (p = 0.16). The in-hospital mortality rate was 13% in patients with right versus 3% in patients with left anterior descending artery occlusion (p = 0.09), and hypoxic brain damage was seen in 4% in those with right versus 0% in those with left anterior descending artery occlusion (p = 0.20). The mechanisms of the high complication rate in patients with acute right coronary artery angioplasty may involve the Bezold-Jarisch reflex or distal embolization of thrombus. These findings suggest that particular caution needs to be exercised when applying mechanical reperfusion strategies to patients with acute right coronary artery occlusion.