INCIDENCE, PREDISPOSING FACTORS, ACUTE COMPLICATIONS, AND PROGNOSTIC IMPLICATIONS OF INTRACORONARY THROMBUS FORMATION DURING PTCA

Besides coronary artery dissection, intracoronary thrombus formation is known to be an important mechanism for acute coronary occlusion in the course of percutaneous transluminal coronary angioplasty (PTCA). Therefore, we analyzed 210 consecutive patients (217 dilated stenoses) to define the incidence and potential predisposing clinical and morphological factors of intracoronary thrombus formation. Intracoronary thrombus formation was angiographically detectable in 11 % of the cases, a dissection in 21 %. Acute PTCA-related coronary occlusion (incidence = 5.5 %) was significantly associated with intracoronary thrombus formation (p < 0.001) but less so with dissection (p = 0.074). Acute redilatation after an initially successful PTCA was almost exclusively necessary in patients with intracoronary thrombus formation (p < 0.001). Univariate analysis demonstrated the following factors to be significantly associated with intracoronary thrombus formation: Irregular lumen of stenosis (p = 0.006), stenosis at branch point (p = 0.012) and unstable angina pectoris (p = 0.001). Patients with intracoronary thrombus formation did not show a worse long-term prognosis regarding clinical events compared with a matched group (average follow-up of 20 months). Conclusion: Luminal irregularities within the stenosis to be dilated and the clinical syndrome of unstable angina pectoris are predisposing factors for PTCA-induced intracoronary thrombus formation, suggesting that preexisting local activation of the coagulation system plays an independent role for intracoronary thrombus formation during PTCA. Although intracoronary thrombus formation increases the risk for acute complications during PTCA, the long-term result is not adversely affected.