Impact of intravascular ultrasound guidance on directional coronary atherectomy.

In contrast to the luminogram of coronary angiography, intravascular ultrasound (IVUS) has proven to accurately assess both coronary lumen and vessel morphology due to its 360 degrees imaging capacity. Directional coronary atherectomy (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 IVUS guidance in a head to head comparison to on-line quantitative coronary angiography (QCA) on the result of DCA. In 16 consecutive patients IVUS demonstrated significant residual plaque mass after DCA irrespective of a satisfactory angiographic result. After a mean 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 stenosis by angiography of 23 +/- 10% and IVUS of 35 +/- 14% (p < 0.05) and finally a minimal 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 stenosis dimensions. After additional cuts IVUS revealed further luminal improvement with an area stenosis by angiography of 25 +/- 16% and IVUS of 21 +/- 18% (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). Intraprocedural use of IVUS is superior to on-line QCA to assess the immediate result of DCA. IVUS-guided DCA results in more effective atheroma debulking than luminographic evaluation. Results of larger follow-up studies are needed to substantiate the intraprocedural advantage of IVUS with DCA.

[Visual assessment or quantitative measurement of coronary stenoses: significance for "prima vista"-PTCA]. / Visuelle Einschätzung oder quantitative Vermessung von Koronarstenosen: Bedeutung für die "prima vista"-PTCA.

In 300 patients with 339 coronary lesions the percent diameter stenosis (%-DS) was assessed both by visual estimation and by digital quantitative coronary angiography (DQCA) by use of an on-line computer work-station. The decision for coronary angioplasty in the same setting ("prima vista"-PTCA) was based on history, evidence of ischemia and visual estimation of %-DS. DQCA measurements of the 339 stenoses revealed a normal distribution of lesion severity with a mean of 58.4 +/- 11.3%. In contrast to DQCA visual estimation led to a bimodal distribution with a nadir at approximately 55% between two peaks at approximately 45% and approximately 75% and a mean of 70.5 +/- 19.6%. Visual estimation underestimated lesions in the range of 30-55% and overestimated the %-DS between 55-99%. Visual estimation revealed a %-DS > or = 60% in 251 stenoses (74.0%) of the 339 lesions, an estimate that led to subsequent "prima vista"-PTCA. Conversely, DQCA revealed only 184 stenoses (54.3%) with a %-DS > or = 60%; thus, 86 stenoses (25.3%) did not meet the morphologic indication criteria for PTCA. The bimodal distribution of stenosis severity according to visual analysis with an overestimation of borderline stenosis severity reflects at tendency for "self-referral" of patients for PTCA. DQCA serves as an objective tool in the decision-making process for PTCA and may reduce "cosmetic" interventions or justify to defer PTCA. Especially in the selection process for "prima vista"-PTCA DQCA-quantification of stenosis severity is recommended.

On-site digital quantitative coronary angiography: comparison with visual readings in interventional procedures. Implications for decision and quality control.

In order to review the morphological criterion for an interventional procedure, diameter stenosis (%DS) of 226 coronary lesions in 200 patients undergoing elective coronary angiography with an option for 'prima vista' angioplasty (pPTCA), was assessed on-site by both visual 'eye balling' (EB) and independent digital quantitative coronary angiography (DQCA) by means of an angiographic workstation. Compared to DQCA, EB overestimated the %DS between 50 and 80% and accounted for the majority of discrepancies with overestimation up to 45%. Concordant estimates of %DS by both methods were observed in only 10 of the total of 226 stenotic segments; in 20 of 226 cases, EB underestimated %DS up to 20%. EB revealed a %DS > or = 60% in 166 stenoses (73.4%), an estimate that led to subsequent pPTCA. However, only 119 (52.6%) of these lesions had a %DS > or = 60% as assessed objectively by DQCA. With regard to the criterion for PTCA 47 of 166 performed pPTCA (28.3%) would not meet the indication criteria based on objective DQCA information. EB and DQCA (+/-5%DS) had concordant results and criteria for pPTCA only in 103 of 166 coronary lesions (62.1%). These results lead to the conclusion that, on-site and on-line DQCA by an independent cardiologist eliminates both under- and overestimation of stenoses as seen with EB. DQCA supports immediate decision-making and appears necessary for reliable evaluation of coronary morphology in an interventional catheterization laboratory setting and may eventually ensure intraprocedural quality control.

[Individual archiving of digital angiocardiograms]. / Individuelles Archivieren von digitalen Angiokardiogrammen.

CD-R will be introduced internationally as a standardized individual archive and exchange medium allowing individual solutions for long-term archiving in a catheterization laboratory. The concept of digital archiving on two CD-R includes a long-term primary basic archive and a secondary one edited by intelligent (medical) data reduction (IDR). The basic archive is automatically composed by a background process consisting of unprocessed images or image series and is fundamental for further transfers, storage, presentations and additional studies. The digital working archive comprises a set of images and image series edited by IDR, as well as the results of morphometric studies as well as identification and documentation data. IDR is based upon the elimination of useless and redundant images series, documentation of coronary interventions on one single representative image and on the reduction of relevant images series and physiological data into an ECG-controlled representative cardiac cycle. IDR edits a redundancy-free set of 130 images (diagnostic study) or only 85 images of an interventional study. Two cardiologists and two cardiosurgeons independently studied 24 IDR-edited angiograms and the corresponding unedited digital angiograms and found no significant differences in the diagnostically relevant coronary morphology and left ventricular function. This study shows that an edited angiogram may not only serve for digital archiving but also form the basis for further evaluation or copies.