Impact of intravascular ultrasound guidance on directional coronary atherectomy

In contrast to the luminogram of coronary angiography, intravascular ultras ound (IVUS) has proven to accurately assess both coronary lumen and vessel morphol ogy due to its 360 degrees imaging capacity. Directional coronary a therectomy (DCA) improves the coronary lumen by removing plaque mass rather than stretching the vessel and compressing the plaque as with conventional percutaneous transluminal coronary angioplasty. In an attempt to optimize the procedural result of DCA we prospectively investigated the impact of IV US guidance in a head to head comparison to on-line quantitative coronary a ngiography (QCA) on the result of DCA. In 16 consecutive patients IVUS demonstrated significant residual plaque ma ss after DCA irrespective of a satisfactory angiographic result. After a me an of 9+/-2 cuts luminal improvement was obtained with an area stenosis by angiography of 39+/-17% and by IVUS of 50+/-10% (p<0.05), a diameter stenos is by angiography of 23+/-10% and NUS of 35+/-14% (p<0.05) and finally a mi nimal lumen diameter (MLD) by angiography of 2.9+/-0.5 mm and by IVUS of 2. 3+/-0.5 mm (p<0.005). After both on-line QCA and IVUS measurements a second series of 7+/-2 cuts were initiated to debulk more atheroma and improve st enosis dimensions. After additional cuts IVUS revealed further luminal impr ovement with an area stenosis by angiography of 25+/-16% and IVUS of 21+/-1 8% (n.s.), a diameter stenosis by angiography of 16+/-11% and by IVUS of 13 +/-19% (n.s.) and finally a MLD by angiography of 3.1+/-0.5 mm and by IVUS of 2.8+/-0.3 mm (p<0.05). Intraprocedual use of IVUS is superior to on-line QCA to assess the immedia te result of DCA. IVUS-guided DCA results in more effective atheroma debulk ing than luminographic evaluation. Results of larger follow-up studies are needed to substantiate the intraprocedural advantage of IVUS with DCA.