Abstract:
Background: The evaluation of collateral pathways in coronary artery disease with total chronic occlusion require quantitative knowledge of the collateral function with respect to the morphologic characterization of collaterals.
Methods: In 91 patients (mean age 65 +/- 10 years, 69 male) with total chronic occlusion of a major coronary artery (duration > 2 weeks) collateral function was assessed invasive by Doppler flow and pressure recordings proximal and distal to the occlusion before recanalization. For collateral function form parameters of the Doppler flow profile (systolic, diastolic and combined flow), the constant part of the impedance (cIMP), the frequency dependant impedance, the average of time-resolved conductivity (aCON) and the total blood flow were calculated. Collateral morphology was assessed angiographically by the Rentrop grading, by Levin’s anatomic location classification and by the grading of collateral connections according to Werner. On the basis of Receiver Operating Characteristics the frequency dependant parameters of collateral hemodynamics were validated with the simplified averages.
Results and Discussion: Receiver Operating Characteristics demonstrated no improvement using frequency dependant impedance compared to the constant part of the collateral impedance. The functional parameters aCon and cIMP were better than the total blood flow for the characterization of collateral function. The collateral function improved significantly during occlusion time (aCON in one= 0.20+/-0.17, two=0.22+/-0.25, three and more month= 0.28+/-0.18 cm*s-1*mmHg-1). A predominant systolic, diastolic or combined collateral flow profile was not correlated to the collateral function. Considering the anatomic location of Levin 17 patients had one, 15 two and 24 three different collateral pathways. In the majority of cases (63 of 91 patients) a septal pathway was included. In all patients the comparison of the Rentrop grading, the anatomic location classification and the collateral connection grading showed only for the latter an independent and significant relation with the collateral function. In patients with a single collateral pathway no correlation of the collateral function to the anatomic location could be observed. In reduced left ventricular function (EF<50) epicardial pathways (cIMP =3.3+/-1.0 mmHg*s*cm-1) compared to cases with inclusion of septal pathways (cIMP = 7.7+/-4.4 mmHg*s*cm-1) were associated with better collateral function. According to the Werner grading of collateral connections CC2 collaterals (cIMP =4.9+/-2.7 mmHg*s*cm-1) preserved regional left ventricular function better than did CC1 collaterals (cIMP =6.7+/-4.2 mmHg*s*cm-1). CC0 collaterals (cIMP =13.7+/-7.2 mmHg*s*cm-1) were predominantly observed in recent occlusions of 2 to 4 weeks duration, with the highest collateral impedance.
Conclusions: The simplified averages of collateral hemodynamics were sufficient enough for quantitative assessment of collateral function. The angiographic grading of collateral connections in total chronic occlusions could differentiate collaterals according to their functional capacity to preserve regional function and was closely associated with invasively determined parameters of collateral hemodynamics. Only in patients with reduced left ventricular function a correlation between the anatomical locations and the function of collateral pathways could be seen.

Brief Biography of the Speaker:
Dr. Matthias Goernig received a M.D. at the University of Hamburg, Germany, in 1993. From 1993 to 1994 he worked as an Internship at the Max von Pettenkofer Institute for Microbiology in Munich, Germany and at the National Cancer Institute in Bethesda, USA. From 1995 to 1998 he was working at the Clinic for Dermatology, University Hospital of Jena, Germany and in 1999 at the Dermatology Hospital of Leutenberg/Thuringia, Germany. Since 2000 he is at Clinic Internal Medicine (Dep. Cardiology), University Hospital of Jena, Germany. His research interests are in biological signal analysis and the clinical applications of bioelectric and biomagnetic fields.